• Property claim for chawl house in Mumbai

hi, my grandfather has purchased 1 room in chowl via pagri system. in 2003 he made a gift deed for my father saying now no other siblings will b part of it. now since 2003 my father is owner of this property & all rent receipts,electricity bills are on my father's name. now suddenly in 2014. my grandfather is asking my father to sell this property & make 3 parts. 1 for grandfather & other to for my uncle & father.we don't want to sell this. please advice