Really urgent. Related to rented flat.

I stay in South Mumbai. My building is a paghdi building and is a 100 years old. We have a big flat and this is given for rent in the name of my great grandfather (chotubhai Parikh).My great-grandfather and my grandfather both have passed away but my grandmother is alive. My father is an adopted son.We have been staying in this flat since 70 years. My father who is an adopted son has been staying since 30+ years in this flat. Then rent receipts were in the name of my great grandfather but after some time they were coming in the name of my grandmother. We have all the bills and reciepts of us staying here since many years and have payed the rent always. Can anyone remove us from the flat after my grandmothers death?