How can I stop my mother from giving property to brother?

My father left self-acquired property without a will, and now it is shared with my mother and brother. However, my mother now wants to pass her share entirely to my brother, leaving nothing for me. How can I prevent my mother from giving her full share to my brother legally? How can I prevent the property from being sold without my consent (since I stay out of town)? Can my mother create a valid will to give her full share of the self-acquired property to my brother, ignoring the Hindu Succession Act for women? How can I prevent this, or what are my options? Kindly assist as I am stressed.