What do i do in this situation

I am residing property of my sister's father in law house since 2001. He has expired in same year. I was not paying to my sister or his husband since then. We had our own house in different area before residing in above property. Me and my sister and her husband mutually agreed that after selling said house they will buy a new property for me and my old mother who died in 2006. After selling said house they refuse to arrange the house for me. When i asked the money which came out from selling my old house., they refused to return back and told me those money was belong to her and my brother, who had their name in to said property. Since year 2014 my sister's husband and his son is threatening me to vacate the house which is property of of their grandfather.My brother is staying with us. He has no interest in this matter. He advise us to vacate the house and find somewhere else. He is in touch with my sister's family regularly. I am nothing to my brother and sister now. My sister husband and his son threatened me to kill me and my family if i shall not vacate the house. They come time to time to threaten me. I have given a complaint in local P.S. regarding this. After this too they are threatening me still. I shall be homeless if i leave above house, i don't have any money to get a house on rent. I am doing temporary job on little money There was no written agreement/ commitment between us. S My sister'son is govt employee in local courts, he has contacts with some criminals/ goons. I am in state of depression right now.Should i get legal assistance in this case?