Legal heir for Pagdi house

My grandfather took a house in Pagdi system around 1940 aprox in dadar area. He passed away in an accident post which the name transfer did not happen in my fathers name. I was a kid when my father also passed away in 1986. Post which the rent receipt was were moved under my grandmothers name. After my grandmother passed away, we went to landlord to get it transferred to my mothers name but it could not be done as one of my uncle had issued an objection to the landlord. Now my mom stays in that house and we 2 brothers are the only legal heirs of the said property. I stay in other city for my work and my elder brother has taken up another place in the same vicinity. We both grew up in the same house but i moved out 10 yrs back to other city for my job. My mother continues to stay there. The rent receipt is still in my grannys name. my mother is retired and has not taken any keep interest in the property name change. However i fear that after my mother passes away, my brother would grab the entire property and would not allow me to stake claim. Due to certain reasons I do not see it going under redevelopment yet. I fear my mom wont live for many years from here. 1) How can I safe guard my right on the property. (Its ancestral, bought by my grandfather in 1940) 2) Can there a provisional affidavit made between both brothers that after my mother, both the sons would have equal rights. All my paternal uncle or aunts have passed away, hence no one can stake claim. 3) Is my mother's WILL be sufficient for me to safeguard my equal right. 4) I am in favor of a 50-50 sharing with my brother, but he is not. what should I do. 5) the owner does not stay in maharashtra so transferring the house in anyone else's name as of now is difficult. Hence what provision can i do to safeguard myself. 6) What if my brother does not allow me to enter the house. pls help.