When a child with additional needs turns 18, the law changes overnight.
Parents who have spent years speaking to doctors, managing appointments, handling benefits and making day-to-day decisions can suddenly find they no longer have automatic authority.
Nothing may have changed in real life.
But legally, everything has changed.
This is sometimes called the “cliff edge” at 18.
Why Turning 18 Matters
Once a young person becomes an adult, parents no longer have automatic decision-making powers.
That can affect:
- medical treatment
- care arrangements
- benefits
- bank accounts
- housing
- education and support
- long-term planning
Even where the young adult clearly still needs help, professionals may not be able to take instructions from parents unless the right legal authority is in place.
Common sense does not always solve this.
Paperwork often does.
The Problem Many Families Face
Many parents assume someone will explain what needs to happen before their child turns 18.
Sadly, that often doesn’t happen.
Families may only discover the problem when:
- a doctor will not discuss treatment
- a bank refuses to speak to them
- benefits need managing
- a care decision has to be made
- social services or medical professionals ask who has legal authority
By then, it can be stressful, slow and expensive to put things right.
Start Planning Before 18
The best time to start thinking about this is usually from around age 14 onwards, especially where there is an Education, Health and Care Plan.
Planning early gives families time to consider:
- whether the young person can make a Lasting Power of Attorney
- whether a deputyship may be needed
- who should manage benefits
- how future gifts or inheritances should be protected
- what happens when parents are no longer able to act
Leaving it until the 18th birthday can make everything harder.
The Main Options
Appointeeship
An appointee can manage Department for Work and Pensions benefits for someone who cannot manage them personally.
This can be useful, but it is limited.
It does not give authority over wider finances, medical treatment or care decisions.
Lasting Powers of Attorney
A Lasting Power of Attorney allows someone to choose trusted people to make decisions for them.
There are two types:
- Property and Financial Affairs
- Health and Welfare
However, the young person must have mental capacity to make the LPAs.
This means LPAs may be possible for some young adults with additional needs, especially where capacity fluctuates or they can understand the decision with proper support.
If LPAs are possible, it is much simpler and cheaper than going to court later.
The negative factor is that you can’t apply until the child is 18, and they must have the ability to understand what Lasting Powers of Attorney are:
Key Capacity Requirements for making Lasting Powers of Attorney
A person has capacity if they can:
- Understand the information relevant to the LPA.
- Retain the information long enough to make the decision.
- Weigh up the options and consequences (benefits/risks of attorneys).
- Communicate their decision (by any means).
Specific Considerations for LPA
- Time and Decision Specific: Capacity must be assessed at the exact time the LPA is signed.
- Capacity Assessment Areas: The donor should understand the nature of the property/finances or health/welfare decisions they are delegating.
- Certificate Provider: A certificate provider must certify that the donor understands the LPA and is not under pressure.
- Presumption of Capacity: Adults are assumed to have capacity unless proven otherwise. If there is reasonable doubt, an assessment by a qualified expert is recommended to ensure the validity of the document.
It will take as a minimum 8 weeks plus to process applications for Lasting Powers of Attorney after they have been completed, so the ideal scenario is that all relevant people are present on the 18th birthday and sign the forms that day and they are posted off to the Office of the Public Guardian first class tracked that same day.
Deputyship
If the young person cannot make an LPA because they lack mental capacity, the family may need to apply to the Court of Protection for a deputyship.
A deputyship can allow someone to make decisions on behalf of the young adult.
Most deputyships deal with property and financial affairs.
Health and welfare deputyships are possible, but the Court is usually more cautious about granting them.
Deputyship can be helpful, but it is usually:
- slower
- more expensive
- more formal
- subject to ongoing supervision
That is why it is worth checking whether an LPA is possible first.
Protecting Benefits and Inheritance
Another important issue is money.
Many vulnerable young adults rely on means-tested benefits or care funding.
An outright gift or inheritance could affect their entitlement.
That does not mean parents or grandparents should avoid leaving them anything. It means the gift needs to be structured properly.
A trust can often be used to protect the young adult while reducing the risk of benefits or care funding being disrupted.
This is especially important when making Wills.
Parents Need a Succession Plan Too
For many families, Mum or Dad is the main advocate.
They know the appointments, routines, medication, behaviours, preferences and warning signs.
But parents will not always be able to do everything.
A good plan should consider:
- who steps in if parents become ill or die
- who manages money
- who deals with care providers
- who understands the young adult’s needs
- whether trustees, attorneys or deputies are needed
This is not just legal planning.
It is family protection.
Practical Steps For Parents
If your child has additional needs and is approaching adulthood, consider:
- Reviewing their Education, Health and Care Plan
- Asking whether adult social care should be involved
- Checking whether they can make LPAs
- Considering appointeeship for benefits
- Taking advice about deputyship if capacity is lacking
- Reviewing your own Wills
- Considering whether a trust is needed
- Writing down key information for future carers or family members
The earlier this is done, the better.
Final Thought
Turning 18 should be a milestone, not a legal crisis.
But for families of vulnerable young adults, the change can be sudden and unforgiving.
With the right planning, parents can avoid many of the problems that arise when no one has authority to act.
The most important message is simple:
do not wait until the 18th birthday.
Start early, take advice, and make sure the right protections are in place before they are needed.
Need Help Planning Ahead?
If your child has additional needs and is approaching 18, or if you are worried about Wills, LPAs, deputyship or protecting benefits, I can help you understand the options.
To make a Will or LPA or review one, contact:
Stephen Pett CmpnSWW, AffSTEP, DMS
The Professional Will Writer
📞 01323 766766
✉️ steve@theprofessionalwillwriter.co.uk