I need ADVICE please!

So let’s start off by saying my parents and my fiancé pretty much hate eachother, which makes the holidays hard because they both expect me to pick to spend it with them. Well this Christmas, his brother was supposed to be flying in to spend it with him, which is great! So I can spend it with my parents. Yesterday his brother texts him and lets him know he probably won’t be in until Christmas Day. Now my fiancé is depressed because he has to spend Christmas <a href="https://play.google.com/store/apps/details?id=com.glow.android.eve">Eve</a> alone because his family is out of state and his friends all have their own family ...I definitely don’t want his to be alone. I explain this to my parents and ask could I spend Christmas <a href="https://play.google.com/store/apps/details?id=com.glow.android.eve">Eve</a> here so he won’t be alone and I can spend all of Christmas Day with them. My mom lashes out and says how dare I break Christmas tradition of spending both days with them and if I don’t show up she is “done” with me. I feel like I can’t win! Any advice?

I wish I could make everyone happy!