Should I Not Invite My Dad to My Graduation?

Assalamu alaykum everyone, I'm going through a tough time right now. Alhamdulillah, I’ll be graduating with my law degree in July. I’ve got two tickets for guests, and I plan to invite my mother and sister. I’m hoping to find some extra tickets so my other sisters and a friend can come too. But my mum is pushing me to invite my dad instead of her. Honestly, he’s been really awful. He’s hit my mum badly in front of us many times, he’s been abusive to me and my siblings, he’s never been there emotionally, and overall he’s just a terrible person. I don’t want him at my graduation at all-I think it would spoil my mood, and since he never cared about my studies, why should he get to come? My mum says that by not inviting him, I'm sinning and disobeying my father. I don’t feel that’s true, because I just want to protect my special day from being ruined. Am I wrong here, or is my mum right? Jazakallahu khayran