Possession of property in Mumbai Slum.

I have a Room in Mumbai slum (kurla) which was bought by my father in 1975 on pagdi system. Then he moved to government quarters in 1990. After he shifted Many of my relatives stay in those Room. I have valid Rent receipt from Chawl Owner (I believe approved by magistrate) , I have electricity bill on my name, Ration card Aadhar card. Also after my father deceased transfer of ownership is legally done. Recently my uncle passed away who used to live in this room for almost 15 years. He doesn't have any valid proof that proves that he is the owner of the Room. My two cousins (son of my deceased uncle) is not agreeing to leave this room, claiming this is his fathers Room. I believe he has Driving licence, Voters ID and also aadhar card on this address. I have filed the legal suit on him since last 1 year, I really dont know where the case is going further. My concern is, he is staying in that Room for almost 10 years now. is it true that, who has the possession of the property always has the edge? Can you please advise me on this issue?