Change location v

Contesting a will due to mental capacity

It is not uncommon for a beneficiary or family member to decide to contest a will because they believe the deceased did not hold the adequate testamentary capacity to create the document.

You may believe that you or your child were unfairly excluded from a will (or not given your fair share of the deceased person’s estate) due to their lack of mental capacity on the part of the testator.

If so, Gerard Malouf & Partners can help you file a claim and challenge the will based on the mental incapacity of the testator at the time the will was made.

Defining testamentary capacity

Testamentary Capacity is the ability to understand the moral obligations of creating a will, including how estate decisions will impact on family members and other dependents after the will maker’s death.

In some cases, an inheritance dispute will occur because an individual or group of people believe the person who created and signed the will did not have the mental capacity to make the decisions relevant to succession planning.

Normally, a person in “sound mind” is free to leave their property to any person or organisation they wish. However, this can lead to family provision claims if they do not adequately provide for each person who has, at any time, been financially dependent on the deceased, estate or other support.

Elder law seeks to protect individuals who are of sound mind and their rights to decide to whom their estate should go in the event of their death (within the bounds of succession laws.)

There are several things that need to be established to prove that a person still maintained testamentary capacity at the time they gave instruction to draft their will. The will-maker must be able to understand:

  • What a will is (how it dictates who gets an inheritance)
  • Their general financial position (what assets and property they have to distribute)
  • Who they should leave their estate to in accordance with Australian inheritance law
  • What options do they have for their personal preferences in disbursing their estate


The testator cannot have any disorder or delusion of the mind that is changing how they dispose of their property or allowing someone else to influence how they write their will. A dementia diagnosis preceding will-signing may be grounds to challenge a will.

If this is the case, challenging the will can result in the Supreme Court setting the document aside and using either an older will or an official succession formula to distribute the deceased’s estate. Challenging wills is somewhat more complicated than merely contesting a will.

How does the Court measure testamentary capacity?

If someone has chosen to contest a will due to a lack of testamentary capacity, the plaintiff must be able to prove that the deceased lacked the knowledge or understanding required to create the will.

This can be proven by obtaining an opinion, preferably in writing, from the person’s treating doctor. Additionally, the solicitor used to witness and create the will should also be able to provide their opinion on the capacity of the deceased.

Contesting or challenging a will

Semantically speaking, contesting wills and challenging wills are two different types of will disputes. Contesting a will simply addresses the terms of the will, without saying the will itself is invalid. Challenging a will is an effort to throw out the will, based on the testator’s mental capacity at the time they wrote it.

The Supreme Court or High Court will take a number of factors into consideration when deciding on a person’s testamentary capacity. This includes their understanding of moral obligation, their mental health, any possible external pressures.

In some cases, it will be uncovered that the will reflects the wishes of a beneficiary more than the deceased. This can occur when an individual lacking mental capacity is coerced to change their will through manipulation. If another party can be shown to have exerted undue influence over the deceased person suffering from mental incapacity, the will can be thrown out.

While it is not uncommon to challenge a will due to a lack of testamentary capacity, not many wills are set aside on these grounds. This is because any will that was prepared by a competent solicitor will have been subject to various controls and measures to satisfy the knowledge that the will-maker held the requisite testamentary capacity.

It can therefore be challenging to make a successful inheritance dispute based on this claim. If you believe a family member has left a will made without the legal capacity, your first step should be to contact a contesting wills lawyer to help build your case. You need to act swiftly; you may only have 12 months from the date of the death of the deceased person to file a family provision claim and dispute the will.

Your lawyer can halt efforts on the part of the executor to disburse the estate and begin the process of challenging the will. If successful, a former will can be reinstated and proceed to probate, or (if the deceased person died otherwise intestate), the matter will be settled in estate court according to the laws of succession.

Proving the deceased lacked mental capacity

The primary goal when challenging a will on grounds of mental incapacity is proving that the testamentary ability of the deceased was compromised at the specific time that they wrote their will, or that the will was signed under duress or undue influence.

If someone showed up in the deceased’s life after they were already showing signs of dementia, and a pre-existing will was subsequently replaced with a fresh one naming the new person as a major beneficiary, it can be a sign that the will was signed under undue pressure. Wi9lls signed under such influence can be successfully challenged.

The new beneficiary could be a stranger who entered the deceased’s life as a romantic partner, a business partner or a “long lost relative.” A case might be made that they used their position and took advantage of the deceased’s failing mental capacity to manipulate them.

It is also possible that a family member acting in a caretaker capacity might try to exert undue influence to change a will and provide more for themselves out of the estate by pressuring a will-maker. Other family members may feel that the final apportioning of the estate is unfair.

Proving that the deceased lacked mental capacity and was unable to legally sign a new will can be difficult if they took steps to make their will ironclad. If the testator arranged for a medical examination to prove they were of sound mind, obtained documentation to that effect, and had both their doctor and their solicitor present when they signed the will, it can be difficult to challenge it and win in court.

You need legal advice from qualified contesting wills lawyers who can examine all of the documentation surrounding the circumstances of writing and signing the will. They can talk to witnesses who were surrounding the deceased at that time, and find out whether there was medical confirmation that the testator had the mental capacity to make a will.

If you can’t challenge a will due to mental capacity, you can still contest the will if you feel the way that the deceased’s estate was split up is unfair or doesn’t comply with succession laws. You’ll still need a will disputes attorney to help you try and reach a settlement, go through mediation and negotiations, and represent you in court if necessary.

Remember that the executor of the will does not have the final say in how an estate is disbursed. They are simply responsible for carrying out the processes laid out in the will for disbursement of the deceased’s estate. If the will is thrown out, and an old one reinstated, the executor may change. If there is no old will to reinstate, the Court will take over.

Your estate dispute lawyer may be able to come to an early settlement agreement by negotiation with other beneficiaries of the estate and getting all of them and the executor to sign a Deed of Variance. This alters the will terms to give you your fair share of the inheritance as agreed upon by all parties. This can allow the estate to be settled quickly and all parties can receive their inheritance in short order.

If you think that your loved one was suffering from mental incapacity and/or was under undue influence when they made their will, you should consult a lawyer to find out if you have grounds to challenge the will.


More Case Summaries

© 2021 
Contesting Wills
 — Gerard Malouf & Partners

Website Design by MediaSmiths

Your location is currently: