My parents are divorcing and i have really mixed feelings

I'm not sure where i should be posting this but i need to talk about it.

Both my parents have done some bad things but my stepdad has always scared me way more since he could easily hurt me if the feelings arose. He usually just raised his voice and threatened me and my brother, despite us being adults now. (i am the youngest and I am 20) He has been getting into multiple serious fights with my mom that usually left me having severe panic attacks. throwing things and yelling and slamming doors, and its finally over. we think the relationship is fully over this time. It's one less stressor in my life but I'm sad.

I was finally accepting the fact that I'm an uncle now (my stepsister has 2 small kids) and I was starting to form relationships with the kids but it is almost Christmas and our original plan of having 10 people for Christmas has shrunk to 3 and my step sister is possibly not letting her daughter (who is probably very confused) see her grandma for the holidays. on top of this I have to be the adult right now as my mom struggles with what is happening. i just hope she doesn't start lashing out again in this emotional time. I am trying to be supportive but i have always struggled with supporting people .