Need help on Gift Deed

Hello All, This is my first experience to write something like this; please pardon I may lack knowledge in this regard. So here goes my question, I am single lady, software developer by profession and youngest of all my siblings. Eldest is my brother and then my sister; both married. So the flat where I have been staying since my birth along with my parents and brother's family having his wife and two daughters; This flat was gifted by my grandmother to my brother when he was minor and my father being guardian for this property. Here starts the worrying part; as people changes sooner than seasons. So being only son to my father, my brother is a pampered child where he got everything he had wished, even the partner of his choice. Now my worry is if in future any unwanted circumstances happened with regards to this flat, do I have any right to claim on this flat? Can the same flat be gifted again to my mother? Can my brother sell the flat and have all benefits alone? Do my uncle and aunts also has rights on this property? Do I and my sister has any right on this flat? I and my sister always being supportive whenever our family/our home had down time. I really feel helpless for this and request guidance. Thanks