My father is physically and emotionally abusive towards me and my mother

I am a 16 year old girl from West Bengal, Kolkata. My father has been abusing me and my mother physically for as long as I remember. He would throw slangs at us, hit us, kick my mother and use abusive language towards us. He often gets angry at small matters and has isolated us from my mother's maternal home. He has never given proper financial support to my mother. We are living off of my grandfather's salary. He has sometimes hit my grandmother and often has arguments with my grandparents. Whenever he gets angry, he degrades me and my mother and says that he will kick us out and sell me. From a few years, his physical abuse has lessened but he has increased the mental torture on us. He would not let me and my mother meet my maternal grandfather and aunt. He has recently received an apartment of my grandfather. We are thinking about moving into that apartment, however whenever he gets angry he shouts at us and says that he will not let me and my mother live in that apartment. My mother and I are scared to take a legal step against him because my mother is unemployed and a full-time housewife. If we take take a step against my father then my grandfather will not let us live in his house anymore and we will have nowhere to go. Both me and my mother are mentally and physically exhausted due to my father's behaviour. If we complained an FIR against him, will we be given protection and financial assistance by law? My mother and I do not want to live with him and suffer anymore. Any advice on this situation please?