Repeat Domestic violence committed by father on mother

Repeat Domestic violence committed by father on mother. My father keeps physically beating up my mother brutally whenever she goes with him to his relatives place. This happens whenever she gets into silly arguments with her in laws (SIL MIL) Due to constant physical abuse over the years she has become weak both physically and mentally and is having incidents of paranoia about his safety now. Even when I had a bad argument and had called the police home after a fight when I was not present there my mom supported him stating that he didn’t do anything to her. Even now she simply says it’s okay it’s your own father and she simply suffers but accepts the beatings and asks me not to complaint to police or lodge an FIR on ground of domestic violence. All my mothers side relatives know about this abuse and continue keeping quiet. But they all know these incidents and ask to move on and let them do what they want in their relationship in order to avoid further escalation. What’s the legal course here? Thanks a lot in advance