I'm sorry you have bad actors in your family, Luna! My parents just left my house; they came over to tell me that I was "ruining" the holidays by not attending where my sister's boyfriend is welcome. This boyfriend was dating the both of us at the same time, and she was married at the time. Though they won't repent, I'm going to "the bad place" for not letting it slide. No apologies necessary, just get over it. *really?!*
I feel like hosting a giant Christmas dance party for those not wishing to spend the holidays with jerks. I guess, bottom like is, you don't have to be nice to people who are not nice to you. You don't have to return fire, but there is nothing wrong with letting BIL know that you feel slighted. The Bible says that he is blessed who craves correction.
BTW - my favorite pair of pants is a brand called Lunachix