Does the Oldest Child Automatically Make Decisions for a Parent?

Written by James Tyrrell · Reviewed by Anthony Dalton · Last reviewed 9 April 2026

“As the eldest, I handle all mum’s affairs.” It is said with confidence in families up and down the country, and it is almost entirely without legal foundation. Birth order, family seniority, and the fact that everyone in the family agrees — none of these things create legal authority over another adult’s finances or health decisions. Understanding why matters enormously, and not just for the eldest child.

What the Law Actually Says

There is no provision in English and Welsh law that grants one adult decision-making authority over another adult based on birth order, age, or family role. None. Not in the Mental Capacity Act 2005, not in family law, not anywhere else.

Every adult is treated as an autonomous individual with the legal right to manage their own affairs, regardless of their age or family circumstances. When an adult can no longer manage their own affairs due to loss of mental capacity, the authority to step in comes from a formal legal document — not from being born first, being the most capable sibling, or being the one the family trusts most.

This confuses a great many families, who assume that at least one of the following must be true: the eldest child has authority, the most involved child has authority, or the child who everyone agrees should handle things has authority. None of these assumptions hold up legally.

What “Next of Kin” Actually Covers

Hospitals use the term “next of kin” routinely, and this reinforces the misunderstanding. Being listed as someone’s next of kin means the hospital has a contact — someone to call in an emergency, someone who can provide background information, someone who cares. It does not confer any legal authority over medical decisions, and it gives no financial rights whatever.

The term has no statutory definition in England and Wales that creates decision-making power. An NHS leaflet may list a relative as next of kin; a bank statement will not. A hospital may involve next of kin in conversations; it is not legally required to follow their instructions.

The Common Scenario in Detail

The situation typically unfolds like this. An elderly parent — perhaps in their 80s — gradually becomes unable to manage their own financial affairs. The eldest child has always been the one the family turns to, and has been informally helping for some time. Nobody thought to make a formal arrangement because it was never needed before.

Then something changes. A care home requires payment. A property needs to be sold. Or the bank notices unusual transactions on the account and asks to verify the account holder’s wishes. Suddenly, the eldest child is asked for documentation. Legal authority. And there is none.

At this point, the parent may no longer have the mental capacity to make a Property and Financial Affairs LPA. The eldest child is not named in any legal document. The family is unanimous that this person should be in charge. None of it matters to the bank, the solicitor, or the care home.

Banks: What Happens Without an LPA

Banks are bound by their own regulatory obligations to protect their customers’ money. If a bank believes or becomes aware that a customer no longer has mental capacity to manage their account, they will restrict access to sole accounts. This is not the bank being obstructive — it is the bank following the rules designed to prevent financial abuse.

To release funds or accept instructions on behalf of the account holder, the bank requires formal legal authority. A registered Property and Financial Affairs LPA naming the eldest child (or anyone else) as attorney is the recognised document. Without it, the account is frozen. Direct debit payments to care providers, standing orders, and access to savings — all blocked.

It does not matter that all three children agree their eldest sibling should be in charge. It does not matter that the eldest child has been paying the parent’s bills for two years. The bank cannot act without documented legal authority.

Medical Decisions: Involvement Is Not Authority

In a hospital or care home setting, NHS and care staff should consult family members and take their views seriously as part of a best-interests assessment under the Mental Capacity Act 2005. The family’s knowledge of the person — their wishes, beliefs, values, and character — is genuinely useful to clinical staff making decisions.

But “being consulted” is categorically different from “having authority.” Without a Health and Welfare LPA in place, no family member can give or withhold consent to medical treatment on behalf of the patient. The treating clinician makes the best-interests decision, informed by the family’s input — but not bound by it.

See our guide on whether a doctor can override an LPA for more detail on how medical decision-making works in practice.

No Court Will Automatically Award Authority to the Eldest Child

Even in a Court of Protection application for deputyship, birth order is irrelevant. The court considers what is in the best interests of the person who has lost capacity, and looks at who is best placed to act as deputy. That might be the eldest child, or it might not be. The court does not default to seniority.

Where siblings disagree about who should be appointed, the court process can become contested and significantly more expensive. The Court of Protection will determine what is best — but that determination takes months, costs money, and involves the court having ongoing oversight of the deputy indefinitely.

When Everyone Agrees — It Still Is Not Enough

One of the most frustrating aspects of this situation for families is that unanimous agreement among siblings does not change anything. If all three children agree that their eldest sibling should manage their parent’s finances, but there is no registered LPA, that agreement has no legal effect. Organisations — banks, solicitors, care homes, HMRC — cannot act on a family consensus. They need a document.

This is not a technicality. It is a fundamental principle of how property rights and decision-making authority work in English and Welsh law. The law protects people who have lost capacity from having their assets managed informally — even by well-meaning family members.

What Actually Gives Legal Authority

• A registered Property & Financial Affairs LPA — Gives the named attorney authority to manage the donor’s finances once registered. The donor names their attorney of choice — eldest child, youngest child, a trusted friend, or a professional.
• A registered Health & Welfare LPA — Gives the named attorney authority to make health and welfare decisions when the donor no longer has capacity. Again, the donor chooses their attorney.
• A Court of Protection deputyship order — Where no LPA exists, the court can appoint a deputy. The process takes months, involves ongoing court supervision, and costs significantly more than making an LPA in advance. See our guide on what deputyship involves.

Real Example: Three Siblings, One Problem

Michael, Susan, and Paul are the children of their 82-year-old father, Derek. All three agree that Michael, the eldest, should handle Derek’s finances. Derek himself has always said the same. When Derek’s dementia progresses to the point where he can no longer manage his affairs, Michael goes to the bank to arrange for Derek’s pension to be redirected and for the care home standing order to be set up.

The bank asks for the LPA. There is no LPA. Michael explains that everyone in the family agrees. The bank asks again for the LPA. Michael explains that Derek himself always said Michael should handle things. The bank still cannot act without legal documentation.

The family must now apply to the Court of Protection for a deputyship order. The process takes around six months. During that period, a family member covers Derek’s care costs out of their own pocket and attempts to recover them later. The stress, delay, and cost are entirely avoidable. A £92 registration fee for an LPA would have resolved the situation before it arose.

Common Questions About Family Authority and LPAs

This guide was last reviewed and updated on 9 April 2026. Information is based on current legislation and OPG guidance for England and Wales.

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