If he ever says anything to you, just point out he's a pussy because he hides behind his fat and nothing else. Before he beats you to death, just ask him "what about that guy" and just point to someone larger than him. Just make him feel like a wuss. If he's too scared to even talk to someone bigger, than talk to someone bigger than him and discuss how much of a wuss he is for not talking to someone bigger, and I bet you'll have that person to help you out if the problem persists.