Can a mirror will be changed after a spouse develops dementia in Queensland?

You can change your own will if you have capacity, but you cannot change your spouse’s will, and an attorney under an Enduring Power of Attorney cannot sign a will for them. When one spouse develops advanced dementia and loses testamentary capacity, reviewing existing estate plans becomes critical, but informal alterations or assumptions about attorney powers can lead to costly Supreme Court litigation.

Mirror wills vs mutual wills

In everyday practice, couples frequently execute mirror wills (also called reciprocal wills). In a standard mirror will structure, each spouse leaves their entire estate to the surviving spouse, and provides that if the other spouse does not survive, the estate passes to their children or designated beneficiaries.

It is vital to distinguish between two legal concepts:

1. Standard Mirror Wills: The wills mirror each other in content, but either party remains legally free to revoke or change their will at any time during life without breach of contract.
2. Binding Mutual Wills: The parties entered into a binding legal contract agreeing to execute reciprocal wills and promising not to revoke or alter them without the other’s consent. If one party alters their will after the other loses capacity or passes away, equity may enforce the agreement by imposing a constructive trust over the estate assets for the agreed beneficiaries.

Reviewing the original estate documents is the essential first step to determine whether a binding mutual-will agreement was created.

What happens if the capable spouse passes away first?

If a wife’s will leaves her estate to her husband, and the husband currently resides in aged care with advanced dementia:

• Asset administration: If the wife dies first, her estate passes to the husband according to her will.
• Attorney management: The husband’s appointed financial attorney under his Enduring Power of Attorney steps in to manage the inherited funds strictly for his maintenance, healthcare, accommodation, and comfort.
• Subsequent succession: When the husband later passes away, his own existing will dictates how the remaining assets are distributed (for example, equally among their adult children).

Where the adult children are already both the appointed attorneys and the ultimate secondary beneficiaries under both wills, leaving the existing arrangement in place often achieves the intended family protection without expensive court intervention.

Statutory wills under the Succession Act 1981 (Qld)

If leaving the estate to a spouse with dementia would create serious asset protection risks, expose funds to unintended claims, or produce an outcome clearly contrary to what the incapacitated spouse would have intended, an application can be made to the Supreme Court of Queensland for a statutory will.¹

Under sections 21 to 28 of the Succession Act 1981 (Qld):

1. The Court has jurisdiction to authorise a will to be made, altered, or revoked for a person who lacks testamentary capacity.¹
2. The applicant must obtain leave of the Court and provide detailed evidence, including medical assessments of capacity, financial records, family relationships, and the terms of any prior wills.²
3. The proposed will must be one that is or may be a will that the person would make if they had testamentary capacity.³

A statutory will application is a formal Supreme Court proceeding and requires specialised legal representation.

Practical steps to take

If your spouse has been diagnosed with cognitive decline or dementia:

1. Locate original documents: Gather the original wills, enduring powers of attorney, and any binding financial or mutual-will agreements.
2. Assess capacity: If cognitive decline is in early stages, obtain an urgent medical assessment of testamentary capacity under the historic Banks v Goodfellow standard.⁴
3. Review beneficiary nominations: Check whether superannuation binding death benefit nominations (BDBNs) and life insurance nominations require updating.
4. Seek specialist succession advice: Discuss whether creating a testamentary discretionary trust or seeking a statutory will is appropriate before taking any irrevocable steps.

For further insights, listen to the discussion on Legal Matters Episode 28 or explore our guide on challenging a will on grounds of dementia in Queensland .

This article is general legal information and does not constitute legal advice. If you need assistance with wills, dementia capacity, or statutory wills in Queensland, contact Bell & Senior Lawyers on (07) 5532 8777.