True, as long as he stays there he will be fine. Try to catch a plane here or anywhere else the US has an extradition tready with and that's another story. So its not just the US he cannot enter as long as they have put his info thru interpol of course.
Then again, if terroists on terror watch lists can get thru then it's probably not that hard to get around....

He has more money then Allah so acquiring a fake passport should not be that difficult actually.