Son's Widow right in in-law's property

Dear Sir, Greetings of the Day! (Property at Kalkaji, New Delhi) Kindly note that we are three brothers (no sister). After death of our father, in year 2007, we all three brothers given the Relinquishment Deed in favour of our mother who became the absolute owner of the property. In year 2016, my middle brother got expired due to Cancer. He never had any kids, also had very bitter relationship with her wife since his marriage. Parents had allowed them to live on Ground Floor. My mother was badly tortured by this daughter-in-law and, ultimately my mother could not resist her torture moreover due to young son's death and old age ailments. Though, we all have legal papers with us, including Mutation of property in my Father's name. Finally my mother shifted and living with me at Haridwar. The property ownership as per RD is Ground Floor (occupied by daughter-in-law), Ground Floor, Third Floor with Terrace Rights. I seek your kind advise in the matter suitably. With regards, Deepak Kumar Mob.[deleted]