Update!
We played again and he was good. A ton of bad stuff happened actually and he was still good, so I'm thinking the issue has been solved. Huzzah for sitting down and working out problems like mature adults!
Our DM has done some stuff too to make it a little less frustrating for him too I've noticed. Not going easy on him, but just kind of working with his play style.
For example, we were talking to people trying to get info on a werewolf we were hunting, he asked someone about who clearly would have no idea, and she didn't but she pointed us in the right direction. (Well I don't know NOTHING about that, but i heard from Mrs. Carpenter that her cousins farm to the north has had their cattle gettin mauled by some sorta creature!) Something that was actually recomended on this thread.
Our party got beaten up pretty badly, he himself was unconscious, the bad guys got away, and he was fine.
There was ONE instance when some bad guys were able to avoid a booby trap we set for them, and was he kind of a downer about it, a little more than you should be about something like that. But it really wasn't much, and I think the only reason I even noticed is because I was looking for it.
So yeah, I think we're good now. Although he definitely still has the "us vs the DM" mentality, which could be bad in the future, but for now I think we are good. If anyone has any problems with someone in the group, I HIGHLY recommend just sitting down and working it out in a civilized manner, hopefully your results are as good as ours.