Some of you may know this store from elsewhere on the web (an in-laws board on iVillage)....
My FIL refuses to hire professionals to do any work on his house, on the assumption that all plumbers, electricians, carpenters, and other specialties are crooks who are out to cheat you by telling you that something is wrong when it really isn't it. So, my ILs house is in deplorable condition after decades of FIL's half-a$$ed amateur repairs. In particular, the house has a serious mold and mildew probelm, in large part because the roof has never been replaced (built in 1964, the house has its original roof with multiple layers of bad patch jobs). One year, I ended up in Urgent Care the day after Thanksgiving and the day after Christmas because of an allergic reaction to all the mold in the house. In particular, I develped an allergic reaction called atopic dermatitis which is a weeping rash. I then developed a secondary bacterial infection in the rash.
The ILs' attitude ranged from "there's no mold problem here" to treating me like the heroine in "The Princess and the Pea". ("Well, maybe there's a teeny little bit of mold, but the only reason that it brothers you is because you're such a high-maintenance princess.")
So, my hill was that I not have to attend events in that house. It took about six months in marriage counseling to bring DH around to the point where he would stand up to his parents.
We did a couple of Thanksgivings and Christmases in restaurants, then when DH and I bought a house large enough to host everyone, we started holding things at our house. Even at that, we still have to listen to FIL say that it just isn't Christmas if he can't open presents in his own home. One year I smiled sweetly and told him he was welcome to cart his presents home and do so if he wanted.