Senior citizens cheated by son and no one taking care of her

My mother is unsound mind taking treatment in NIMHANS my brother sold all our jewels and took all her post office saving and even mortgage my mother's property by taking sign of her but she does not know what is going around her if we say also she doesn't believe because she loves his son and my big sister always coming and torturing to sell the property as my sister and uncle or in debt she was never even bothered to see her parents since twenty years of marriage but now she and her husband are asking to sell my mother property to fill their debt I am consured of my mother as she is unsound and 60 years old I fear she will be sent to road bythis selfish children as a daughter how can I help to save her rest of life