Does he get to keep that when he loses?
Jill Stein certainly seemed like she did when she raised all that money for a phony recount - she was accused of using those funds to pay off her campaign debts.
“Does he get to keep that when he loses?”
If he’s corrupt, yes
He will start a “Foundation” that he and his family will manage and all of his assets will be put under its control, he wont make a salary, but all of his and his families expenses will be paid.
Its an amazing scam that political people can do.
Of course this is just my opinion.
Re: “Does he get to keep that when he loses?”
Legally?
No.
But he can donate any money left over to other Democratic candidates, or to Progressive political organizations, or start his own PAC, or retain it for any election he may seek in the future.