Persecution of my grand father by uncle and his son.

Respected lawyers I need a suggestion. My grand father aged around 90 having two child my uncle (elder than my father) and my father. My grand father gives more attention to uncle and his two sons since their birth. And as my father got job in Army they persecute him also for money and work when he was on leave. Since 6-7 years as my father stopped all financial aid as to upbringing us since then my uncle and his sons started persecuating my grand father for money. They beat, abuse, stop from eating, stop treatment etc. My father requested my grand father to come with him as he can't saw him as the way his life was but he refused to do so. My father is afraid of slander in society as to file any case against uncle and his sons. Last year my father deposited ₹50000 in my grand father's account for his treatment and living but that was also withdrawn from his account by uncle's son this year. I'm very anxious of my father anxiety about grand father's health, property, money. I'm very obliged for your kind attention towards this issue.