Since Scabby Doug has already offered the opinion that the guy is a dick, I won't bother to offer my opinion, which is that he is an arse-hole. Anyone who doesn't understand a basic concept like "all instruments in a session should be tuned to an agreed upon pitch" should not be allowed to own an instrument that requires tuning. Be sure that representatives of the tuning police are on hand at your next session so they can confiscate his guitar.

Bruce