Complaint against my brother and sister in law

My mother and elder sister are getting harrased by my brother and his wife. I lost my dad this year in April 2021 and ever since my father has expired, both of them find some or the other reason to torture her mentally. My mother is a senior citizen and the house we live in, is under her name . My sister in law provokes my brother every day and under her influence, he creates some or the other issues at home which is seriously affecting my mother's health. We are three sisters and one brother out of which my younger sister and brother is married . After my dad's demise, my brother is willing that we should move out of the house and he also has clearly stated that sisters should not get any share in my mother's property. Situation has gone worse and now every now then , my sister in law and my brother not only misbehaves with us but also beats us . Since my brother is a lawyer, he threatens us to push behind the bars by filing forge complaint against all the sisters . My elder sister and me are not married and we are currently staying with our mother . Looking at the recent past incidents, I really fear that both of them can harm us physically as he has already threatened to kill us . Kindly suggest