Rights of grandson in maternal grandfather's self acquired property

My maternal grandfather (nana) purchased a house in 1968. My mother got married in 1985 and I was born in June 1986. However, my mother expired in Dec. 1986. Thereafter, my Nana expired in 2014 without any will. My mother's brother (mama) and his family are currently in possession of the residential house. My mama is now in planning to sell this house and is reluctant to share the sale proceeds with me. I wanted to know if legally, I have any right in this property and can file a case to stop my mama or claim my share. Please help.