This is funny. He’s not being investigated for using the treatment. Just for claiming it was tested in an FDA approved study, which it wasn’t. So you don’t have to cry anti-trumpism. And the investigation didn’t even start because he was in the news, just because of a wrong email address accident.
Dr Zelenko Under Federal Investigation By Muller Prosecutor Of Impeachment-Flop Fame
And it doesn’t seem like a serious investigation, so you don’t have to panic.