Domestic violence against my mother and father

My parents got married in 1996, my father wasn't working back then. My grandparents were working professionals. Grandfather is a doctor & grandmother retired as a government school principal in 2015. They have been mentally torturing my mother since 2006, but my mother stayed & didn't utter a word. They have not physically abused her yet, but threaten her to throw her out of the house or kill her. My father has no property or asset on his name, neither does my mother. They live in my grandparents house, so we had no option, but to stay due to low financial status of my parents. We are 2 siblings my brother & me(female) & we live away from home due to studies & job. My mother is a working woman as well (govt teacher). My grandfather keeps finding clues to attack her verbally & with his aggresive tone & way of speaking. Nowadays my mother is not able to cook food due to her health issues & duty commitments. So they prepare limited food, my father told me if he eats vegetable one time of the day, next morning he has only chapati to eat. My grandparents come from an upper middle class family as they have land assets & built a big house, so it's not the case of their affordability. My father wasn't brought up well, so he earns bare minimum to run a family & my mother's salary is used for our education and stuff. We are capable now to move out & live in a rented space, but I want to take a legal action against my grandparents if I am only left with the option of leaving the home. My mother is traumatised to live there, but has no guts to shift from there alone. I have a voice recording couple of months old, where my grandfather is threatening my mother that he'll throw her out of the house, and tell her to move away from his way, or else he'll hit her. We do have proof for the torture of all the previous years, but trying now to get a legal help, because my parents are not fighting now, they are helpless. My parents money was all utilised in our education overall. We took debts from our relatives & then cleared them as we got money. My grandparents didn't give any money for our education, as they had promised earlier to my mother when we were young. My mother was employed since 2007, they kept all her salary until 2012. Now they clearly deny & say they didn't even touch my mother's salary ever. Early 2000s my grandmother was buying land worth 13k, in which my mother gave 7k. There was no acknowledgement for it & in 2019 my grandmother gave that 7k amount in cash back to my mother and said , I don't owe you anything. There has been fraud with my parents. So I wanted a legal help to proceed in the right direction. My maternal uncle & family also do not come ahead in our support and help us legally or as a family. Everyone has accepted this situation & told my mother to adjust. My grandparents didn't want us siblings to study, as they didn't educate my father well & wanted us to stay dumb, but my mother revolted & since then she is facing all the trauma