How to deal with abusive father and what decisions to take in future to ensure good life for me and my mother?

It's going to be a very long post , but if you can read and help me or suggest me I'll be very thankful to all of you. I'll share everything in detail from beggining. So my (21 M) mom was married a bit late , and her family married her off quickly after she was in depression for 2-3 years ,they selected my father because from 1-2 people they inquired my father seemed to be a good person and decided that he's the best for her without even asking for her choice even though he was earning very low to take care of a family on his own. A few months after I was born he started showing his true colours , getting angry over small things , breaking things , verbally abusing my mother. One thing more that he hid this thing that he was 10 years older than my mom , no one from my mother family even knew this thing , they were under the illusion that he is only 4-5 years older than her , obviously this broke her and upon asking him he just abused her.

Also divorce wasn't an option at that time because at that time it wasn't considered good or whatever , taboo. She was shattered.

Since my childhood I have seen him getting angry over small things , he would verbally abuse me , my mother. Sometimes he would throw a plate full of food on the floor. Once I was in maybe UKG or LKG and dropped some juice on the floor by mistake which he brought from market , he took all my clothes off and threw me out of house , where I stood crying for 10-15 mins before he let me in. He would do these thing frequently and beat me so much. He even recorded me crying sometimes on his phone and prompting me to say that I would be careful not to commit mistake next time.

Sometimes my mother would plead him by lying in his feets , and he wouldn't listen. My mother never told these things to someone as she was scared what would happen to her later and also she wanted me to have good life so she suffered through all of this. He never let my mom go anywhere because his main concern was who'll cook food, he straight forwardly says that he can't eat outside food and so he refrains my mom from going anywhere like at some relative's house or a friend'shouse. Sometimes when my mom would get fever , he won't even make the morning tea instead she would insist my mom to make even while knowing that she isn't well.

Sometime he wouldn't take her to doctor saying that she'll remember not to get sick again .

Last year I overheard my mom talking to my aunt , that he r*pes her , even when my mom would say no. But at the time I did nothing. A few months after that I went for a one day trip with my friend and my mother called me scared and crying around 9pm that he's verbally abusing her which I heard on the call and forcing her to have ***, at that time I was away from home and couldn't do anything so i told her to lock herself in my room and keep recording if anything happens and he was continuosly banging on the door. Next day when I arrived I confronted him about this , at first he was like nothing happened , then he got angry started abusing her and told me that it's important in marriage and she has to do this.

Last year when my maternal grandmother was visiting us , there was a fight on the same topic and she even abused my grandmother and she was begging him to stop these fights but he didn't listen , she was literally standing with her hands folded and crying , and at the time of this event my nani is suffering from a bad depression due to my nanaji's death but my father doesn't care.

I still have a bit of anger towards my maternal grandparents that why they married her my mom without proper inquiry and never supporting her divorce option. But I'm forever indebt to them for their favours which they are still doing , my father didn't have much money at the time of my birth , and my grandparents wanted me to have a good life so they built a good home for us from their own money , they are paying my education fee till date. At the time around 80% of things in my home are given from them. Since both of my maternal uncles are doing good so my nana and nani has helped us a lot financially with their own money , still my father abuses my nani and my late nanaji because of 2-3 incidents at a family function which weren't that serious. He has anger issues,a lot of ego.

My mom has gotten a lot of money from her family which is very more than sufficient for both of us to leave and live on our own. But she is stuck in this relation. What can we do in such a case ? I have two years before I finish my engineering and get a job . Since i'm an adult now he doesn't abuse physically but verbally he still does that. He is harassing her a lot mentally , I hate to say this but sometimes he behave like a Rap**t does when he is full of lust and since my mom has now got a bit stronger mentally and says NO directly to his face , he starts abusing her again. Depsite of all this my mother has told him straight that she doesn't want to maintain any physical relation and ask him to leave peacefully in the house, and not to interfere in our life. But when my mom has to visit her friend or go somewhere to relatives house, he still creates some sort of drama to soil her mood.

For him , my mother was always like a slave to him. He wants her to do work , obey him and stay at home. Earlier my mother couldn't wear any suit or slippers of her choice if he didn't like him but now she has become stronger mentally and takes her decision but she is still mentally distubed because of him. Outside of home he's very good and a religious person but only me and my mom knows what we go through daily , he keeps on disturbing her daily by doing small things intentionally. One moment he's normal and next moment if you day something he doesn't like or approve of he get super angry. Indirectly she's after my mother's money and wants to take control of it. During several fights he has said that you have a lot of money , you got it without doing anything even though she got all from her parents .My mom wasn't even allowed to spent her money which she got from her parents without asking him. Now she doesn't allow him to control her and he has started doing fight more.