A few thoughts, having been caught on the bad side of a player group in the past:
- Do you see this person outside of gaming? Are they easier to deal with in a non gaming situation? Maybe he wants to socialize with your group, but just isn't into the gaming part of it anymore.
- Try setting up a non-gaming event. See if he shows for that. Maybe it's the game, and not the players he's frustrated with.
- Is there something else going on in their life that is distracting them? Sometimes, when there are other things in your life going bad, the last thing you want is for your entertainment to be a frustrating experience as well.
- Tell them they just can't expect to be planned around, when they have not shown up in the past. If they still want to play, fit them in with a "guest role" for the times they show. Maybe this will be less stressed, and may enjoy the chance to play the "bad guys" for a change.
- Finally, if he continues to be a problem, just stop actively inviting him. If he still wants to show, tell him the ground rules for behavior. Just make sure EVERYONE in the group is willing to sick to the same standards.
While there may be satisfaction in "putting it to him" or his character, nothing is gained from it in the long run, and you've burned a bridge that should have been left on its own.