I think we just let it be ! And every time he post to buy or sell we say something ! Let everyone know who and what he is. Theirs enough of us to make it so hard for him that he's bound to give up and leave .
Who knows it might even be fun ?
We can just disagree with any for sale post he puts up and message any unsuspecting members that show interest in his items. Whether he's selling or wanting to buy. Been doing that for a long time now anyway, as have several others.