Uncle did fraud and made a fraud Will of grandmother what to do

hello sir i am from nagpur. my uncle had a property 5.5 acre land but unfortunately he has expired 2 years before. he was unmarried. my uncles mother has expired last month. we got to know late uncles 1st here legal property holder is mother. my uncles father is alive and have 4 real brothers and sisters. i am elder brothers son. one of my uncle is frauded with us and 3 brothers and sister are together. my uncle made a registered will deed of mother. and submitted will deed to court. that property is already in dispute. in will deed he made himself nominee only. he knew already mother is 1st here. he took mother to his home after my uncle died who had purchased this property. mother was 83 years old. and he made a registered will dead without her mental fit certificate. we are not financially strong. and nobody likes my uncle who is cheating with us. are advocate also didnt give right advice to stop him. we feeling helpless he alone doing all bad things to get this property.