WTB Off-tank?

So, I was going to write about how people on WoW are different from people in real life, but I can write about that any time and I will maybe forget about this little gem.

There is a player in my guild who is very vocally misanthropic.  It's the Internet, so who isn't?  However, last raid he did some stuff that I thought was fairly inexcusable.  We started out doing Sartherion because we didn't have enough people on to try Kel'Thuzad.  He was supposed to be off-tanking.  However, when we went into the portals, there was no tank to be found.  At one point, I could see the main tank list and he was targeting another player; I suspected he had to AFK and put on auto follow or something but why not just say that so another tank would know to pick up the mobs?

Then, when we did get to KT, we were having some trouble getting started, basically just making some stupid mistakes.  At one point, when he could tell we were going to wipe, he bubble-hearthed because he didn't think he should have to pay the repair bill.  But apparently all of the rest of us should?  It's not like he was doing everything perfectly and every single other person screwed up. I'm pretty sure you'd get shot in Vegas for that.