Mentally unsound widow mother lost all her and father's saving to scammers now selling property

Hindu family. Dad died in 2020 without a will. Mom lives in family home - flat registered in Dad's name. Married (seperated, not divorced) sister and her minor son - both mentally unsound live in flat registered in Mom's name. All three survive on my Mom's Govt pension and also less than half of my Dad's Govt pension. Mom is also not mentally sound anymore, has been duped by fraudsters for more than last four years and have lost all her and my Dad's savings, and even loaned from relatives and the same scammers. She also forced my sister to taken a personal lone against her (sister's) life insurance. Sister do not earn. Only 2 flats are left. I am (unmarried younger daughter) estranged from family and get a meager salary, lost all savings while unemployed in 2020-21. I got to know about what Mom did after Dad's death and have tried to stop Mom but she trusts these scammers more than me or our relatives. Now she want to sell off her flat to pay her debt to scammers. I don't want any money/inheritance from my parents and I cannot financially support my Mom, my sister and her son. I am worried that I may inherit those debt. I also don't want them to loose my father's flat - our only asset now!