Dementia and Estate Planning: Act Before It Is Too Late

Updated: 14 September 2026

By Rod Genders | Genders and Partners

Dementia is now among Australia’s leading causes of death. The number of Australians living with dementia is projected to rise significantly in the decades ahead as the population continues to age and curative treatments remain elusive. For families and individuals, the implications extend far beyond medical care. Dementia reaches into estate planning, legal capacity, and financial security in ways that too few people address until it is too late.

This article explains the legal landscape around dementia, why the timing of estate planning is critical, and what every adult in South Australia needs to understand about incapacity planning.

The Scale of the Challenge

Dementia is not one specific disease. It encompasses a range of conditions — including Alzheimer’s disease and vascular dementia — that progressively affect thinking, behaviour, and the ability to manage daily activities. It has no cure and is invariably progressive.

Dementia affects approximately 10% of Australians aged over 65 and around 20% of those over 80. The number of Australians affected by dementia is expected to grow substantially over the coming decades. The disease creates profound legal and financial complications for affected families that are often not anticipated until a crisis has already arrived.

The Critical Legal Problem: Lost Capacity

From a legal perspective, the defining feature of advanced dementia is the irreversible loss of decision-making capacity. Under South Australian law, a person who has lost legal capacity cannot:

• make, alter, or revoke a Will;
• grant an Enduring Power of Attorney under the Powers of Attorney and Agency Act 1984 (SA);
• make or alter an Advance Care Directive under the Advance Care Directives Act 2013 (SA); or
• enter into binding contracts or manage their own financial affairs independently.

Capacity cannot be created retrospectively. Just as insurance cannot be purchased after a loss has already occurred, the necessary legal documents cannot be made after capacity has been lost. They must be in place beforehand.

Where a person loses capacity without having made these documents, the consequences can be severe. Family members have no legal authority to manage the person’s finances, pay their bills, or make decisions about medical care. Applications may need to be made to the South Australian Civil and Administrative Tribunal (SACAT) for the appointment of a statutory administrator or guardian — a process that is costly, time-consuming, and deeply distressing for families already managing a difficult diagnosis.

The Three Essential Documents

1. A Current Will

A Will made under the Succession Act 2023 (SA) sets out how an estate is to be distributed after death and appoints an Executor to administer it. A Will can only be made while testamentary capacity exists. If dementia has progressed to the point where the testator does not understand the nature of a Will, the extent of their assets, or the claims of persons close to them, it is too late.

2. An Enduring Power of Attorney

An Enduring Power of Attorney (EPOA) under the Powers of Attorney and Agency Act 1984 (SA) authorises a trusted person to manage financial affairs during the donor’s lifetime. The critical word is “enduring” — it continues after the donor has lost mental capacity. But it must be granted before that loss occurs. It cannot be created after capacity has gone.

3. An Advance Care Directive

An Advance Care Directive under the Advance Care Directives Act 2013 (SA) appoints a Substitute Decision Maker for medical and personal decisions, and records the maker’s wishes about future health care, treatment, and living arrangements. An ACD gives families clear legal guidance about the person’s wishes and removes the anguish of having to guess what a loved one would have wanted.

Do Not Wait for a Diagnosis

One of the most common misconceptions in this area is that estate planning can wait until a diagnosis has been received. This is exactly the wrong approach. By the time dementia has been formally diagnosed and its progression observed, the window for creating legally effective documents may have narrowed considerably or closed entirely.

The prudent course is to complete estate planning documents while one is healthy, well, and fully capable. These documents should be reviewed periodically and updated when circumstances change. Families should discuss these matters openly, so that every person involved understands their role and the wishes they are expected to carry out.

Genders and Partners has been advising South Australian families on Wills, Powers of Attorney, and estate planning for nearly 180 years. We understand the urgency these issues carry and are experienced in assisting clients and their families navigate them with care and precision.

Want to Find Out More?

If you would like to know more about dementia, incapacity, and estate planning, the specialist team at Genders and Partners is here to assist.

When it comes to Wills, Probate, Deceased Estates, asset protection and estate planning in Australia, you can trust the oldest law firm in South Australia – Genders & Partners – to guide you through the tough decisions to create the best solution for your individual needs.

If you have any questions or would like further information, or a quick phone call to discuss, book a timeslot for a free 15-minute phone consultation.

We can help you to protect yourself and your family. We look forward to being of service.

More Incapacity Planning and Advance Care Resources

• What You Need to Know About Advance Care Directives in South Australia
• Advance Care Directives in South Australia
• What is an Enduring Power of Attorney and Why Do I Need One?
• How to Address the Most Overlooked Legal Consequences of Dementia
• The Looming World Crisis of Incapacity

All these and many more dementia, incapacity, and estate planning topics are available for discussion with the oldest law firm in South Australia.

This article revised and updated 14 September 2026.

DISCLAIMER: This article provides general information about dementia and its legal implications in South Australia. It does not constitute legal or medical advice. The law described applies under the Succession Act 2023 (SA), the Powers of Attorney and Agency Act 1984 (SA), and the Advance Care Directives Act 2013 (SA). Dementia prevalence figures are drawn from publicly available sources and are indicative only.