When an elderly parent changes their will shortly before passing away—leaving the lion’s share to one child while cutting back gifts to others—family disputes almost inevitably follow.
If the parent suffered from cognitive decline, experienced hallucinations, and worked with an unqualified will writer who made drafting errors, can the disappointed relatives successfully overturn the will in court?
Under Singapore law, the answer is far from straightforward.
In YHJ v YHK and others [2026] SGHCF 28, the Family Division of the Singapore High Court upheld the fifth and final will of a 92-year-old patriarch, despite his Parkinson’s diagnosis, low cognitive test scores, drafting mistakes, and allegations of relentless pressure by his favoured son.
Here is a plain English guide to the three legal grounds used to contest a will in Singapore, how the courts evaluate mental capacity, and why this high-stakes multi-million-dollar estate dispute was dismissed.
The Background: A Fractured Family and a Rushed Final Will
The deceased patriarch built a substantial fortune in leather trading and real estate, owning 11 valuable Singapore properties and several family companies.
Between 2015 and June 2020, he executed four successive wills with an established law firm. In his earlier wills, assets were distributed among his children and two grandsons whom he had helped raise.
However, family relationships deteriorated sharply in late 2020:
- The Daughter’s Conflict: The deceased’s daughter (the 2nd Defendant) opposed the sale of a joint property and questioned her father’s mental capacity through lawyers’ letters.
- Secret Recording Devices: Disaffected family members secretly planted audio recording devices in the patriarch’s home and bedroom to monitor his late-night conversations with his biological son (the Plaintiff).
- The New Will: In November 2020, less than three months before his death, the 92-year-old patriarch engaged an unqualified will writer recommended by his nephew. The fifth will was executed at the Plaintiff’s residence.
The new will significantly favoured the Plaintiff—increasing his inheritance by tens of millions of dollars—while drastically reducing provisions for the other children and accidentally leaving one grandson with nothing due to a legal drafting oversight.
The grandson (the 1st Defendant) challenged the validity of the final will on three classic grounds:
- Lack of testamentary capacity;
- Lack of knowledge and approval; and
- Undue influence.
1. Did the Patriarch Have “Testamentary Capacity”?
To make a legally binding will under the landmark test in Banks v Goodfellow (reaffirmed in Singapore in Muriel Chee), a testator must:
- Understand the nature and effect of making a will;
- Appreciate the general extent of the property being disposed of;
- Comprehend and appreciate the claims of potential beneficiaries; and
- Be free from any disorder of mind or delusion that perverts their judgment.
The Medical Evidence vs. Factual Evidence
The grandson argued that the patriarch lacked capacity because he had been diagnosed with Parkinson’s disease with cognitive decline, suffered memory lapses, experienced visual hallucinations, and scored a failing 17/30 on two Mini-Mental State Examinations (MMSE). In addition, the patriarch made an arithmetic blunder during drafting by asking to split a bungalow into three 40% shares (120% total).
The Court rejected the capacity challenge, establishing several crucial principles:
- Dementia or Cognitive Decline Does Not Equal Incapacity: A medical diagnosis of cognitive impairment or even dementia does not automatically strip someone of testamentary capacity. What matters is whether the testator had sufficient mental acuity at the specific time of signing.
- Hallucinations Were Medication Side Effects: The patriarch’s hallucinations were occasional side effects of his Parkinson’s medication (Madopar) rather than permanent psychosis, occurring only around 15% of the time.
- MMSE Scores Are Merely Screening Tools: A low MMSE score does not substitute for a judicial determination of capacity.
- Eyewitness Observations Outweigh Retrospective Expert Opinions: Independent witnesses present on the signing day—including the will writer, his wife, the deceased’s nephew, and an independent advocate and solicitor certifying an accompanying Lasting Power of Attorney (LPA)—testified that the patriarch was lucid, alert, articulated clear wishes, and even negotiated the will-writing service fees.
- A Rational Explanation for Disinheriting Relatives: Excluding his wife from direct gifts was rational because she already owned 8 of the 11 properties in joint tenancy (which passed to her automatically by survivorship). His decision to favour the Plaintiff over his daughter was fully explained by the bitter breakdown in their relationship.
2. Did He “Know and Approve” of the Will’s Contents?
Where a will is prepared under suspicious circumstances—such as where a major beneficiary drafts instructions or provides the venue—the court requires affirmative proof that the testator genuinely understood and approved the contents.
Here, major suspicions arose:
- The favoured son prepared a typewritten note setting out proposed changes.
- Over $1 million had been transferred into joint accounts with the son shortly beforehand.
- The lay will writer made legal errors, including mistakenly assuming property ownership structures.
- The Grandson’s Disinheritance: The deceased swapped two properties between his two grandsons. But because one property was held in joint tenancy with his wife, it passed to his wife by survivorship and then fell under her separate will (which also gifted it to the other grandson). As an unintended consequence, the 1st Defendant was left with neither property.
Why Errors and Bad Advice Do Not Invalidate a Will
The High Court held that the deceased fully knew and approved the contents:
- Active Engagement: The deceased did not passively adopt the son’s typewritten note. He personally gave verbal instructions, corrected successive drafts, and insisted on including a “No-Contest” forfeiture clause.
- Mistakes of Fact or Law Stand: Under established law (such as Collins v Elstone), if a testator adopts specific words in a will based on mistaken legal advice or a misunderstanding of property ownership, the mistake does not invalidate the will.
- Forgetting what was written in his wife’s separate will or failing to grasp the technical legal mechanics of joint tenancy survivorship was a common layperson’s oversight—not proof of a lack of knowledge and approval.
3. Was the Will Procured by “Undue Influence”?
The 1st Defendant relied heavily on secret audio recordings showing that the Plaintiff spent months badmouthing his siblings, accusing an adopted brother of having “bad genes,” complaining about past inheritances, and warning the patriarch that his daughter was trying to control his money.
The High Court dismissed the claim of undue influence, reiterating the strict legal boundary in probate litigation:
| Concept | Legal Meaning in Probate Disputes | Result |
|---|---|---|
| Persuasion / Influence | Guilt-tripping, arguing, appealing to affection, or exploiting grievances. | Permissible (does not invalidate a will). |
| Undue Influence (Coercion) | Pressure so overwhelming that it destroys the testator’s free agency, forcing them to sign something they do not want. | Unlawful (invalidates the will). |
The Court highlighted that:
- Persuasion Is Not Coercion: A parent is legally entitled to have a favourite child and make unequal distributions. Even if the son’s conduct was self-serving and manipulative, it did not amount to coercion overpowering the father’s free will.
- Objective Grievances: The patriarch was not acting on paranoid illusions. He was genuinely furious at his daughter for defying him over property sales, engaging lawyers against him, and planting secret recording devices in his bedroom. In fact, the patriarch independently took steps to evict her and terminate her company employment.
Practical Lessons for Estate Planning
- Lay Will Writers for Multi-Asset Estates: Engaging an unqualified will writer saved nominal legal fees but triggered years of bitter High Court litigation. A qualified conveyancing lawyer would have immediately conducted land title searches and prevented the accidental disinheritance of the grandson.
- Check the Property Title (Joint Tenancy vs Tenancy-in-Common): You cannot gift your share of a joint tenancy property in a will if you die first—it passes automatically to the surviving joint owner under the rule of survivorship.
- Get a Contemporaneous Medical Assessment: If a testator is over 80, frail, or diagnosed with neurodegenerative conditions like Parkinson’s or dementia, have an independent doctor or psychiatrist conduct a formal testamentary capacity assessment on the day of signing.
- Independent Execution and Attendance Notes: Lawyers and attesting witnesses should take detailed contemporaneous attendance notes in the testator’s primary language or dialect to prove mental clarity and free will.
Frequently Asked Questions (FAQs)
Does a diagnosis of dementia or Parkinson’s automatically invalidate a will in Singapore?
No. Testamentary capacity is a legal test, not a medical label. A person with mild cognitive decline or early-stage dementia may still execute a valid will if they understand what they own, who their beneficiaries are, and the nature of the will during a lucid interval.
What is the difference between persuasion and undue influence in a will challenge?
Under Singapore probate law, undue influence requires proof of coercion—showing that the testator’s free will was completely overborne so that they signed something they did not want to sign. Persistent persuasion, appeals to family loyalty, badmouthing siblings, or being the “favourite child” does not meet the high threshold for coercion.
What happens if a will contains a legal or factual mistake?
If the testator was of sound mind and consciously adopted the words of the will, a mistaken belief regarding the legal operation of a clause or ownership structure will generally not invalidate the will. The court will not rewrite a will simply because poor legal advice led to an unexpected or harsh outcome.
Why did the grandson end up with no property under this will?
The patriarch intended to give him a property held in joint tenancy with his wife, assuming his wife would die first. Because the patriarch died first, the property automatically transferred to the surviving wife under the right of survivorship, leaving the grandson with nothing under that clause.
Disclaimer
This article is provided for general educational and informational purposes only and does not constitute formal legal advice. Contesting a will, assessing mental capacity, and navigating probate litigation involve complex evidentiary and procedural considerations under Singapore law. Individuals dealing with disputed estates should consult a qualified Singapore probate and estate litigation lawyer.