There’s a lot people can get away with if they have money or connections, especially when they have family in high places supporting them.
Although he may have been under investigation by the FBI and the Department of Justice for his supposed actions in the past, even the mere mention of such an investigation can jeopardize someone’s career, if not lead to an outright demotion or job loss.
There’s always a chance he might have been associated with individuals involved in illegal activities in the past. However, as you mentioned in your post, the principle of "innocent until proven guilty" rarely holds true when the major media outlets decide to derail someone’s career right when it starts to take off.