He inherited his money, No, not all of what he has.
Has been involved in bankruptcy 8 times, I believe he has a couple of hundred companies so 6 going under is par for the course over the amount of time we are talking about.
And it's been calculated that he'd be worth a lot more if he'd just invested in a managed fund. That is extremely subjective and would depend on when you took valuations etc. It also assumes the right funds were gone into at the right time etc. Even managed funds vary a lot and its not simply a matter of putting your brass in one and hoping. Well not to make that sort of money.
He is not the best businessman by far, but successful he certainly is as he aint broke.