My parents set up a trust for my disabled brother and made my uncle the guardian. Unfortunately he was dishonest and greedy and embezzled it. Fortunately he did this before my parents had even passed, so we had time to come up with a backup plan. (The backup plan was me, and I never felt like I could start my own family as long as I was responsible for my brother, so ... that's been limiting.) Anyway...

... I've often felt like it would have been much safer to either make a legal firm administrators of the fund or at least have multiple family members on it, so that they might keep tabs on each other and make it harder to just steal. I've actually spent a lot of time thinking about what went wrong and what might have been different. If that uncle hadn't died I would probably have spent that time fantasizing about ways to kill him, but, as it is ... I just don't get to retire.

I love my brother and have made peace with most of the consequences of what happened to him, because at a certain point you just have to accept the hand you're dealt and keep going. But the bitterness of what the world has done to us is still in me and I don't think it's ever going to leave.

tl;dr - definitely don't leave just one person, even family, with access to a disabled person's money