first rule of blowing the whistle: before blowing, make sure you can't be traced. your life (figuratively, most of the time...) isn't worth the consequences of being a known whistleblower.
It is a lot more productive to focus on the unfairness of extremely wealthy people not following the law, the illegality of that and how therefore this is fellow is a whistleblower. And probably in dire need of some general support if he's gone up against the sort of people with Swiss bank accounts.