Need advice regarding property

Hi, this is Ms. , I live with my mother (2nd daughter) and grandmother( mother's mother ), Hindu family. my grandmother has 2 daughters. Both are married , 1st daughter is living with her in laws. My mother got divorced when I was 5 years. Now my mother and me , we are taking care of my grand mother. My grand father had left my grand mom when my mom was 10 years. He did not divorce her but had an extra marital affair. My grand ma knowing this applied case in the court and asked for divorce and settlement for 2 daughters. But everything was a failure. Our lawyers got money from grand ma but didn't get any justice. But my grand father married the other woman without divorcing my grandma. Its been years now we lost hope and stopped but now as my grand ma my mom are suffering a lot I would like to know what we must do to get settlement from him and he is retired from state government employment. Kindly help me I just shared what I can, I need justice for my grandmother.