How to sell property in mother name if she is suffering from dementia

My mother is mentally unfit now.she forgets things , she is suffering from disease called"dementia".we have 3 floor house on her name and my brother lives in that with family and he do not allow anyone to enter in that big house .my father went to senior citizen tribunal and they rejected our plea as the property named to my mother and she said in front of tribunal she doesn't want her son to go out because she forgets everything what happened to her last day.she does not know how my brother is behaving with father and herself.he is useing my mother illness.and there were some loan on that property on my brother name because my father was not eligible to get loan but my father cleared all dues slowly in 2 years and he still shows these document as proofs regarding payment of that property as he has purchased that land. he was earning only 38000.and living in rented house at the time of purchasing .so my father decided to make house out of investment .pls tell options