My dad takes away my happiness

Christmas time is my favorite. My dad is very “anti” everything, he always thinks the negative and has a really bad attitude. The last TWO years (counting this one) around the holidays he bitches and complains about sending money (even on bills) and threatens to leave. I have bad anxiety and honestly it’s just making it 10x worse with his constant negativity. He bitches my mom out about all this and she comes to me about it. (Our walls are thin so I normally already hear it all anyway) I just don’t know what to do. I already pay bills here.