My uncle taken my father's property. How to proceed to secure him ?

My grand father bought property in my fathers name in Varanasi when he was child. My father died in 1999 when I was 16 year. From childhood he was suffering from epilepsy and paralysis. My father was 9 brothers and 4 sisters. After his death immediately within 2 years when I turned 18 year he fought with us and took that property by taking signature in stamp paper were he took signature from other bothers too and for name sake we got one small property in Jharkhand 1 portion in the building .Signature was done in the stampaper by me and my mother. Iam only son of my parents. Presently my uncle is running heritage hotel in Varanasi in the same property. Kindly advice whether we can legally fight to get proper share of ours.