My grandfather property & my Maternal Grandfather property

My Father died on 2nd december 2014. My Father Deprived by my Uncle from Grandfather property. My uncle made Fordge Documents in his name and his Wife name. He Constructed a Building on that Land on 3 years ago. Only my Father will be deprived. I want to Challenge that Documents but My Grandfather was a Lawyer of Kolkata High Court. So One Lawyer told me that Documents which my Uncle was made there have my Grandfather Signature and Lawyer said me that My Grandfather Shall be signed on that Documents in our absence, So here have Risk to Challenge that Document. Please I need Suggestion regarding that. 2. My maternal uncles also trying to deprive to my mother. My maternal Grandfater was Police Officer. After his death My mater Grandmother was lived with my mater Uncles on that Property. My maternal Grandmother also Died. Now My maternal Uncles try to Deprive my Mother. They made Record in their name at Local B.L.R.O. My maternal uncles told my mother that She is not entitle to get the Share from that Property. So I need Suggestion.