He screws up way too much stuff: The state that he's in, the office that he's running for, what positions he's held and when, what major events he's ever been involved with.
As for his family, I direct you to the 60 Minutes interview: His wife sat with him through the entire thing, and it struck me as a case of need, so as to prevent him from getting out in left field or to shut it down if his mind started to meander.