Succession rights of single married daughter (adopted)

Hello, I am looking for a legal opinion on my rights over my parental property self acquired by my father who died in heart attack in year 2000, with out any will/testaments. As I told I'm adopted by my father at the year 1956, my mother (who is actually my big sister) also agrees to that, and currently I am also having 3 sons. At the time of my father died, all the properties was on his name, after years my mother transfer all properties on her name, and now I have news that she is making a will, to transfer our home, land and bank accounts to her nephew. My mother is 85 years old and living with us,(me and my husband) we are taking care for all her needs very much ,that's include her medical bills and living expenses etc. My mother feel that daughters have no rights over the property and hence I am contemplating a legal recourse. I have read the Succession act 2005 and understand that I have equal rights on both ancestral and acquired property. My concern is whether my mother can adopt measures like disowning me or adopt her nephew just to nullify my claim, what is the legal implications of such disownment on my claim if the scenario arises, and what are reasons they can cite for disownment. Just for your information, my marriage was arranged, by the will of my father. Kindly advise Neeta Tiwari