Ancesral immovable propery house in a village in Tamil Nadu

An ancestral house in our village Gopalasamudram Thirunelvelly dist in our father's name . ---Our fater died ion 30 Sep 1964 . ---our mothe also died in dec 1998. --- We are two sons and two daughters to our parents They are 1.My sister is elder to me alive 2. Myself alive 3. My brother younger to me ---died in Dec 2016-- My brother's wife and they have one son and on daughter --- all alive-- 4. My sister youngest died in 1997-- her husband also died in 2012-- they have one son and one daughter-- both alive Under the above circumstances who are the legal heir for this ancestral house As we are very old and unable to main this house property we want to sell it .. what are the procedure to be followed particularly my brothers son and daughter and mysister's son all ive abroad My elder sister and son and daughter of my brother and son and daughter of my sister wish to reinquish their rights in all respects My brothers wife -- can she give Power of attorney in my favour for selling this immovable ancestral house What are the procdure to be followed please.