If the jobs too giood to quit, then you really have no choice but to deal. Being family, you can nver go over the guys head without generating a problem, and he's probably not going anywhere.
In that case, you have to realize that you can't change the asshole, the only thing you can do for your own piece of mind is change how you respond to the asshole. If that means you gotta take up Yoga, or put a little sand garden on your desk, or whatever, then just do it. Maybe at the end of the day try writing down the things that bothered you at work, take a look at how petty and lame most of them are, and toss it in the trash, I dunno, different things work for different people. I can tell you with certainty however that if your'e going to stay there, any peace of mind you are going to get is going to have to come on your end, so you may as well work on that.
