Stepping Away from My Father for Peace

Assalamu alaikum, I need some advice. My father has always been harsh and physically abusive throughout my life. His relationship with my mother was never calm, and it got worse after he lost his job four years ago, making my mom the sole provider. Since childhood, he’d hit me for no reason, and I’d just bear it, calming my siblings during fights, taking the hits, and listening to him complain about feeling excluded. Yesterday pushed me over the edge. We’ve been urging my mom to seek divorce so we can live in peace, but she hasn’t because he prevents it or threatens public humiliation. A pointless argument broke out between them, and he hit her and spat on her. Trying to protect her, I struck his back, and that’s when things spiraled. I know I shouldn’t have hit him, but in that moment, I felt I had to distract him from my mother, or he might do something terrible. He then turned on me, threw furniture, blamed me for past events before I was born, hit and spat on me. The saddest part is I didn’t shed a tear, I was so used to it. But then he locked the doors and threatened to kill us all, his shouts were terrifying, we begged him to stop. He only stopped hitting when I said I’d call the police, so he left. We tried to flee, but he waited by the car, tried to hit us again, and the security guard had to intervene. My mother wants a divorce, but he’s withholding a necessary document, even though he yells that he wants one. After we left, he texted threats to block our education-my sister and I are top students and even won a robotics competition internationally. He said he’d do anything to ruin our success and wishes us the worst, following us wherever we go. So, is it Islamically okay for me to cut ties with him? I fear Allah’s punishment, but I can’t imagine a life with him in it.