Dementia, Mental Capacity and LPAs, What Happens if Someone Can No Longer Make Decisions?
When somebody loses mental capacity without a Lasting Power of Attorney, their spouse, partner or adult children do not simply become their legal decision-makers.
When somebody loses mental capacity without a Lasting Power of Attorney, their spouse, partner or adult children do not simply become their legal decision-makers.
That can be a shock to families.
A daughter may have managed Dad’s online shopping for years but find the bank will not let her manage his account. A husband may assume marriage gives him authority over all of his wife’s finances. It does not.
What happens next depends on the decision that needs to be made.
First, capacity is about the particular decision
A diagnosis of dementia, brain injury or another condition does not automatically mean somebody lacks capacity for everything.
Mental capacity is decision-specific and time-specific.
The person should be supported to make their own decision where possible. They should not be treated as incapable merely because the family or professionals think their choice is unwise.
Some everyday decisions can be made through the Mental Capacity Act framework
Where a person lacks capacity for a particular decision, the Mental Capacity Act provides a best-interests framework for others involved in their care.
Not every decision requires somebody to be appointed by a court.
Healthcare and care professionals may make relevant best-interests decisions within their lawful roles, consulting those close to the person as appropriate.
But that does not turn relatives into general legal representatives.
Finances often expose the gap quickly
Banks, investments, property and significant financial decisions require proper legal authority.
If there is no valid LPA or older Enduring Power of Attorney covering the matter, an application to the Court of Protection may be needed.
The Court can make a particular decision itself or appoint a deputy to make certain ongoing decisions.
A deputy is not the same as someone appointed under an LPA
An LPA is created by the individual while they have the required capacity and allows them to choose who should act.
A deputy is appointed by the Court of Protection after the person lacks capacity for the relevant decisions.
The court defines the deputy’s authority, and deputies have ongoing duties and supervision requirements.
The two routes therefore arrive at legal authority in very different ways.
What about health and welfare?
Families sometimes assume that if there is no health and welfare LPA they must obtain a welfare deputyship.
That is not automatically the case.
The Court of Protection can make decisions about health and welfare where necessary, but ongoing personal-welfare deputy appointments are treated differently from financial deputyships and are not required for every care decision.
Where there is a serious dispute about residence, treatment, contact or another welfare issue, specialist legal advice may be appropriate.
What if the person needs a will?
If the person no longer has the required capacity to make a will, a relative cannot sign or rewrite one for them under ordinary family authority.
An application can be made to the Court of Protection for a statutory will.
This is a specialist legal process and should not be confused with deputyship or an LPA.
If this is happening to your family now
Identify the exact problem before assuming you need one large legal solution.
Is the issue accessing a bank account, selling property, consenting to care, resolving a dispute about residence or making another specific decision?
Check whether any valid LPA or pre-October-2007 Enduring Power of Attorney already exists.
Then obtain professionally qualified advice about the appropriate route. The fact that somebody lacks capacity does not mean every decision must be transferred to one representative.
Last reviewed
5 September 2026
Important legal informationThis guide provides general information only and does not constitute legal advice. It is not intended to recommend any particular legal arrangement, course of action or solution. Wills, inheritance, trusts, powers of attorney, mental capacity and related matters can have significant legal and financial consequences, and the appropriate approach will depend on individual circumstances. Professionally qualified legal advice should be sought before making, changing or acting upon important legal arrangements or decisions.