Multi Table vs Single Table Tournaments.
Can't tell him how to run his game but at your game you should start running 2 decks (one being shuffled behind the dealer) while the other is in play. This way it will be much harder for him (or them) to Stack the deck if he is in fact doing that. (It would be kind of obvious though because he would be frequently winning big hands on his button. Or hers.)
As
@Saoliver mentioned it could be signaling. If the cards don't seem to be marked I would watch for this like a hawk.
I know it only sounds like $40 but it's not. It's a couple of hundred because he's winning not losing. And some people don't do it for the $ but because they have an illness so who knows.