Could Alzheimer's affect the validity of a Will?

Admin, 6th May, 2025

Understanding the legal implications for families of loved ones affected by Alzheimer's and other mental health conditions.


When it comes to planning for the future, a Will can protect a person's wishes. However, for families with elderly parents, questions often arise regarding the validity of a Will if the person who makes the Will is suffering from Alzheimer's disease, dementia or other mental health conditions. In this blog, we explore the legal implications of such on the validity of a Will and provide guidance for families navigating this sensitive issue.


Mental capacity and testamentary capacity

Testamentary capacity is a form of mental capacity. It is the mental capacity of a person to legally make or alter a valid Will. For a Will to be valid, the person leaving a Will must possess testamentary capacity at the time the Will is executed. This means they must:

  • Understand the nature and extent of their property;
  • Understand and appreciate the claims which they should have in mind (i.e. recognize the people who have or should have a potential claim to their estate, such as husbands, wives, children and other dependants);
  • Understand the nature and effect of the Will itself;
  • Be free from any delusion that affects their decision-making regarding the distribution of their estate.

The impact of Alzheimer's on testamentary capacity

It is awful to see a parent or loved one battling Alzheimer’s.

Alzheimer's disease is a progressive neurological disorder that, sadly, affects memory, thinking and behaviour. It is upsetting to see that, often, it only gets worse over time.

As the disease advances, sufferers can experience significant mental health issues, cognitive decline and lack of everyday mental capacity to live independently. This can impact their ability to understand and make informed decisions. Given these challenges, it is natural for children to question whether a parent with Alzheimer's can or did have the testamentary capacity required to create a valid Will.

It is important to note that a diagnosis of Alzheimer's does not automatically render a parent’s Will invalid. The key consideration is whether your parent had testamentary capacity at the time the Will was executed. In the early stages of Alzheimer's, your parent may still have had the necessary mental capacity to understand the nature and effect of their Will and make rational decisions about their estate. However, as the disease progresses, it may be the case that their cognitive abilities may decline to a point where they no longer meet the legal requirements for testamentary capacity.


Assessing Testamentary Capacity

When considering the testamentary capacity of a parent with Alzheimer's, several factors are considered, including medical records, witness evidence and the circumstances surrounding the execution of the Will. Here are some key steps families can take to check the validity of a Will when Alzheimer's is a concern:

1. Obtain a Medical Assessment
A thorough medical assessment by a qualified mental health professional can be carried out by meeting with your parent during their lifetime or, after their death, on the basis of documents. This evaluation assesses the testator's memory, understanding and decision-making capabilities. A written capacity report from the healthcare professional can serve as important evidence of your parents testamentary capacity (or lack of capacity).

2. Choose Reliable Witnesses
Having reliable and credible witnesses present during the execution of the Will can help support its validity. Witnesses should be able to confirm your parent’s mental state and confirm that they appeared to understand the nature and effect of their Will. Ideally, witnesses should be trusted individuals who have no interest in the estate to avoid potential conflicts of interest (gifts in Wills to witnesses will fail).

3. Document the Process
Thorough documentation created during the Will-making process can provide additional evidence of your parent’s testamentary capacity or their lack of capacity. This may include video recordings of them discussing their wishes and intentions, as well as written notes detailing the reasons behind specific gifts and inheritances. Such documents can be invaluable in the event of a legal challenge to the Will's validity.

4. Seek Legal Advice
Consulting with an experienced Wills & Probate solicitor is crucial when making a Will whilst suffering from Alzheimer's. An experienced solicitor can provide guidance on the legal requirements for testamentary capacity and help ensure that the Will is executed in a manner that minimizes the risk of future disputes. An experienced solicitor may also suggest additional safeguards, such as a capacity assessment by a geriatric psychiatrist, to further protect the Will's validity.


Challenging a Will on Grounds of Lack of Testamentary Capacity

If your parent’s Will is challenged on the grounds that your parent lacked testamentary capacity due to Alzheimer's, the burden of proof rests with the person challenging the Will. They must provide enough evidence that your parent did not meet the legal requirements for testamentary capacity at the time the Will was executed. This often involves analysing medical records, witness statements and other documents to prove or disprove your parent’s mental health.

The court will carefully consider the evidence presented and make a determination based on the balance of probabilities. If the court finds that your parent lacked testamentary capacity, the Will would be declared invalid, and the estate would be distributed according to the terms of a previous valid Will or, in the absence of such a Will, according to the laws of intestacy.


Conclusion

The question of whether Alzheimer's can make a Will invalid is complex and depends on the specific circumstances of each case. While a diagnosis of Alzheimer's does not automatically invalidate a Will, it raises clear concerns and increases the risk of claims. Investigating through a medical evaluation, discussions with witnesses, obtaining notes related to the Will and seeking legal advice, families can put their mind at rest and ensure that their loved one's true wishes are respected.


Want to chat with a member of our team?

If you have concerns about the validity of a will due to Alzheimer's or need assistance with estate planning, Gosschalks is here to help. Contact us today on 01482 324252 to schedule a consultation with one of our experienced solicitors.

About the author: Ben Marsden

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