That's a tricky one. I have a friend with the same problem. Her best girlfriend always invites herself over, sometimes ends up crashing there for days, drinks, eats, etc etc then leaves without a) cleaning up or b) paying for anything. Quite a frustrating situation.
Maybe ask him the day before the party to contribute something to the mix? ie: "Oh hey, can you bring some dip/chips/etc for the party?" At least get someting out of it, right?
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