Family property dispute

My father owned A piece of land with 1 BHK in Kolkata, a well established store in Assam. After my father’s death, my sister and mother took control of the store and the property in Kolkata. My sister who is a doctor with my mother who was an assistant professor didn’t let me know anything on the financial transaction of the store even though I am one of the legal heir of all the assets. And my sister ensured that my mother cuts off all communication with me to acquire all the property. I am a home maker. And she has brainwashed my mother saying I haven’t been able to do anything in life and I shouldn’t have any say on the financial matters. She even told my mom and convinced her that I am psychiatric patient because she is a psychiatrist. My mother sits at the store in Assam and runs with a trade license on her name and my sister controls and guides her from Kolkata. My mom is a kidney patient. So, my sister told my uncle that if my sister talks to my mother and if anything happens to my mother, my sister will be blamed. Basically, if I speak to my mother, she will blame me if anything happens to her. So, it’s been more that 2 months that I have cut off all communication with her. I feel helpless. Please guide me.