If his character is a valid concept character, cool beens, but this guy does sound like he's being a bit of a jerk.
Of course, you all should have seen it coming and not relied on him to fulfill a party role and instead, made sure it was taken care of, letting him be the useless fifth wheel he wants to be.
'I wanna be useless!' is usually a good sign for someone else to step up and take his role over.
I asked a recent new-to-4e player what he wanted his character to do, and he described how he wanted to run in to battle, and through the sheer grace and power of his attacks, rally his allies. I pointed him at the Warlord. Disgusted with the name and role of "leader", he dismissed it - saying it was just someone who ordered others around. I tried to convince him otherwise, and he just wasn't having it.
So I told him I'd write his own class for him and asked for suitable names for the class and role ("Knight" and "Inspirer"). I went away and came back 45 minutes later with the "Knight" (a level 1 warlord, with all the power names changed).
He loved it and has been happily playing since. Whenever he levels up, I transcribe any new warlord powers, give them flashier names and he picks out what he wants
That said, the game is up if he ever studies a PHB too closely. At some point I'll have to come clean![]()
VIII. A Company member shall give his or her best effort in all tasks for the company, above all, defending the lives and property of fellow members. A member ill-suited to a task shall nevertheless aid those who are. One found by majority to be willfully harming, or allowing the Company or its members to come to harm, shall be expelled from the Company, forfeit all reward, & possibly be surrendered to authorities if applicable.
Griefers are griefers regardless of edition.
Role-playing a character is awesome. Making sub-optimal characters can be a hoot, too, so long as the DM is aware of the situation and takes all of that into account.
Making an intentionally disruptive character with the intention of "breaking" the system is childish. Making the game less fun for everyone else around the table is inexcusable.
I'm kind of appalled your DM hasn't handled the matter, to be honest.
-O