I think there’s one major flaw here:

You’re thinking about this as an average human.

When you have insane amounts of money, you get what you want.

He likely shopped around high price lawyers, but since he’s used to being told he’s right and a genius. He would have hired a law firm that agreed with him and said he’d be fine.

They likely knew better, but told him what he wanted to hear and took his money with a smile.