i wanted to delete this post now

Tell Jon they're trying to get back in the picture. Tell him how YOU feel about that. Then ask him if He'd like you to take your friend and get the drums for him so he doesn't have to deal with what is probably an attempt to for them to reconnect with an easy financial resource. He may like that idea. It sounds like they are in dire straights again, and looking for someone to use. Don't put yourself on his 'betrayed by' list, by keeping it from him, snakes like them would use it against you to get to Jon. They've probably heard you're buying a house and want to move in with you. Getting rid of you would be a bonus in their eyes, one less person to share Jon's cash with. The chances that they are only looking for money are high. I can't imagine Jon would easily forget how they betrayed him, or allow them the chance to do it again. But you have to let him decide how to proceed with this for himself or it may be YOU that gets hurt this time.