Word for word I am with you op. I am in your position, exactly the same.
I am so sorry you are in this position, it is particularly hard without the support of a dp. I so understand this.
My father will never accept he is anything other than perfect, even though he is the same as yours. And you are right, you will be fair game and he will be even worse as you will be on your own.
Your mother (the same as mine) has decided to stay with him, that was her choice, but no way do you need to do the same! No bloody way.
Stand your ground, and see some friends on christmas day? Can you do that? And if you can't, I would not go to their house, no way. Have a lazy morning as you suggested, and then decorate the house and get ready for when the children come home and have the best party and fun once they are home. Tell your mother you can not face going anywhere, and being with your father will make it even harder for you, so that has been decided. You will pop in for an hour or whatever on Boxing day.
It is ultimately about self preservation. You have enough on your plate, and you can bet your life that he will capitalise on your vulnerability. Don't let him!
I haven't seen my parents for three years at christmas, we have bene very low contact, I don't trust him to be kind to my children because my father is so volatile. They are coming for a few hours this year, I am very nervous and worried even just about that. So I understand x 100000000.
Do what works for you. Your mother made her choices a long time ago, and it wasn't your safety and well being in mind.