Age Concern do have good advice, and so do major charities such as Mencap and others.
I understand that for most people, putting a house into trust can be complicated, expensive,and usually unnecessary.
I think in less common circumstances then you need to consult a specialist (STEP) solicitor.
Putting a house into trust for a vulnerable family member may seem sensible, but can have unforeseen complications, and needs careful thought.
I think it may be worthwhile if a house is regarded as an asset for the use of family members, instead of an individual's home.