My father was a government employee and my mother is uneducated house wife. My father purchased an agriculture land of 1 acre with his own money in 1996 but on my mother's name. Now the land's pass books are also on my mother's name (but not registered). I have two elder sisters but no brothers.
I have 15 years old mentally retarded son and spending thousands of rupees for his treatment. I asked 5 lakh rupees to my parents for the surgery of my son. Instead of giving money, my mother wrote a gift of the agriculture land on my name in March 2015 and asked me to sell it or mortgage it. The gift deed is notarized and 5 of my father's brothers are signed on it as witnesses.
Meanwhile my father became very sick and he had been in the hospital for many months so we delayed the registering the gift deed. In October 2015 my father expired, and I performed all religious rites with my own expenses as a son.
Recently my mother had a dispute with my wife and went to live with my sisters. Now she says that she wants to sell the land and also says that the gift deed is not valid because it has not been registered.
Kindly suggest me how to proceed legally in this matter.