Succession certificate

My father died intestate, leaving behind a 1700 sq. ft. flat in Khar. My brother and mother have been residing there, and I do not know what the housing society has been told about the flat. Earlier my brother was very good to me, I believed him totally, but now he is showing his true colours, not wanting to give me anything. In lieu of my share of the flat, I have asked for some compensation, as I am a widow with no property in my name and no sustainable source of income. Today my mother and brother both insist I have no share, I am not entitled to anything. I am living in rented accommodation whereas my brother and mother live in a nearly 6 bedroom flat. His wife and children are in the US (they have beaten up my daughters) and he is just waiting for my mother so that he can sell the flat and move there. I do not have the means to fight him, which he is aware of as he told me he would see me in court. I just want to know how I can get a copy of the succession certificate, first to see if I am mentioned or not, and secondly to ensure he cannot sell the flat and get away with all the money. Please help.