My mum is starting to forget things—can she still make a Will?

Can My Parent Still Make a Will If They’re Becoming Forgetful?

It’s one of the most common (and most urgent) questions adult children face. You notice your parent is becoming forgetful. They're losing track of time, asking the same question twice, or mixing up names. Understandably, you start to wonder: is it already too late for them to make or update a Will?

The answer lies in something called testamentary capacity. This is a specific legal test that determines whether someone has the mental ability to make a valid Will at the time they sign it. Importantly, a diagnosis of memory loss or even early dementia does not automatically mean someone lacks capacity.

The law recognises that capacity is decision-specific, time-specific, and can fluctuate. But there is a point beyond which it’s too late—and unfortunately, many families don’t realise this until then.

This article explains:

• What testamentary capacity means in legal terms

• The four-part test used in Australia (based on Banks v Goodfellow)

• How to recognise if your parent likely meets it—or doesn’t

• What evidence can be gathered to protect their Will

• What happens if capacity is lost altogether

What is testamentary capacity?

Testamentary capacity refers to the legal ability to make or alter a Will. In Australia, the test was laid down in the 1870 case of Banks v Goodfellow and remains the standard today. It sets out four essential elements that a person must understand at the time the Will is made.

Even mild cognitive decline can cast doubt on capacity if these elements are not clearly met. Let’s look at each element in detail.

1. Understanding the nature and effect of making a Will

This means the person must understand that they are:

• Creating a legal document

• That will distribute their property

• After their death

It’s not enough to simply say “yes, I want to make a Will.” The person must grasp the function and finality of the document. This includes recognising that they’re choosing what happens to their assets when they’re no longer alive—and that this document has legal effect.

Signs this element is met:

• They can explain (in their own words) that they’re deciding what happens to their estate.

• They know that the Will takes effect after death, not now.

• They understand that the Will is binding and formal.

Signs of concern:

• Confusing a Will with a Power of Attorney or a bank form

• Believing that making a Will changes ownership during their lifetime

• Inability to recall what a Will actually does

2. Knowing the nature and extent of their property

Here, the person needs to have a general understanding of what they own—not an exact account balance, but an awareness of the overall size and composition of their estate.

For example, they should be able to say something like:

“I have a house in Charlestown, about $30,000 in the bank, and some superannuation.”

They don’t need to know every shareholding or vehicle registration, but they do need to demonstrate an awareness of:

• Real property (e.g. home, land)

• Bank accounts or savings

• Superannuation (if applicable)

• Investments or shares

• Personal possessions of value

Signs of capacity:

• Can list or describe their main assets

• Understands that the estate includes debts (e.g. mortgage)

Red flags:

• Believes they still own property they sold years ago

• Insists they have nothing when they clearly do

• Has no concept of the difference between owning and renting

3. Understanding the moral claims on their estate

This element requires that the person can identify the people who might reasonably expect to be included in their Will, and weigh up the moral or legal obligation to those people.

It doesn’t mean they must leave something to every child or grandchild—but they must at least be capable of understanding who those people are, and why they may or may not be included.

For example:

“I have two daughters. One of them I haven’t seen in twenty years, but I still know she’s my daughter. I’m choosing to leave everything to the other because she’s looked after me.”

This shows capacity—even if it might lead to a challenge later.

Capacity is often called into question when:

• The Will excludes close family members without explanation

• The person includes someone unexpected (like a carer, new partner, or friend)

• The person forgets the existence of a child or spouse

It must be clear that any exclusions are conscious, informed decisions—not accidents based on faulty memory.

4. Free from delusions or undue influence

Finally, the person must not be acting under:

• Delusions that affect how they make decisions, or

• Pressure or coercion from someone else

Delusions might include:

• Believing a family member is dead when they’re not

• Thinking one child has “stolen from them” without evidence

• Imagining threats or conspiracies that affect how they distribute their estate

Undue influence is when another person exerts control—whether through fear, pressure, manipulation, or dependency—so that the Will does not reflect the person’s true wishes.

Examples include:

• A child who isolates the parent from others and brings them to appointments

• A carer who threatens to withdraw support unless included in the Will

• Sudden, unexplained changes in the Will that benefit one person heavily

What if you're unsure?

The most practical step is to get a proper assessment while the person still has capacity—or is at least borderline. If the lawyer has concerns, they may request a written capacity assessment from a GP, geriatrician, or psychologist.

At Reframe Legal, we recommend working with lawyers who:

• Keep detailed notes of the capacity assessment process

• Ask open questions to test each element above

• Are willing to delay signing or request medical input if needed

What happens if it’s too late?

If your parent no longer has capacity, they cannot make a Will—no matter how unfair the existing one may seem, or how much they’ve changed. In that case:

• The most recent valid Will stands, even if outdated

• If there is no Will, intestacy laws apply

• Disputes often follow, especially in blended families or estranged relationships

Final Thoughts

Legal capacity is not about whether someone forgets where they put the car keys—it’s about whether they can meet a specific legal test. But because capacity can diminish gradually, the safest time to act is as soon as concerns arise.

If you're in doubt, don’t delay. It’s far more common to be too late than too early.