How do I stop them?

Anthorn

Bogalot wrote: »

There's a big jump between having a mental illness and lacking mental capacity. If the individual understands what they are doing, then even if their choices are not rational or reasonable they will still have capacity.

OP does your brother have mental health support? What is he spending the money on, does he understand what he is doing?

A lot of assuming and nitpicking there and not true.

Here's what the Mental Health Foundation says about Mental Capacity:

Someone lacking capacity - because of an illness or disability such as a mental health problem, dementia or a learning disability

https://www.mentalhealth.org.uk/a-to-z/m/mental-capacity

The OP has not provided information on the mental illness. All we know is that the brother is "mentally ill". Here's the opening post in case you missed it:

My mentally ill brother keeps racking up huge credit card debts. He owns his own flat and has no trouble getting approved for cards. Is there a way to prevent companies from issuing cards to him?