There are a lot of rumors, one of the main rumors is that he has a closed group on Facebook (S C M), where he teaches people to buy very cheap coins, only to dump them as soon as he sees fit, leaving other people behind with no money left. He takes advantage of new traders who don't know any better.
He is known and has a reputation, so people sort of blindly follow them, specially if they get into this through his channel. He stocks up from his poor followers' money, and gets rich from that. He might give sound advice sometimes, but I'd stay as far away as possible from him. Chris Dunn is a lot more plausible.