Abusive and alcoholic father

My father from what all i remember from my childhood is , him being an abusive alcoholic towards me and my mother,

He once broke one of her bone in the thumb when he came home drunk and hit her hard , And me and my mother have been continuously abused by him and if you try to talk to her , he sees it as a crime like he would say , DO YOU KNOW BETTER THAN ME , he believes he cannot be wrong.

There have been times when my grades were low in childhood due to the fact I was being bullied in school and I wanted to tell him this and ask him to step up for me but he was never there to help , he would beat me with a leather belt continuously because a little boys marks were low , I would lie on the floor begging him to stop.

He still drinks and all these things rush back , all i dreamed of in my childhood were to have a happy family of ours and everytime he drinks even if it's a little that child in me dies more and more every second.

He wants me to accept his alcoholicism and forget his past abuse.

And now when I look at my 17 year old little sister this is highly affecting her mental health , to a bad extent and this hurts me.

I want to beat him up till the time he begs me to stop and give him ptsd about drinking.

Would love some words to sooth myself as today again he is out drinking and we have relatives home and they wonder where it's noon.