1. You can transfer your undivided 1/3 rs share by any non-testamentary means like gift deed or deed of relinquishment in favour of your mother which needs to be registered.
2. After that you mother becomes 2/3 rs share holder of the house and cal sell her share to any person she chooses. However the house is not partitioned and is a family dwelling house, the purchaser may be reluctant to buy her share only of your brother is not ready to sell his 1/3rd share.
3. It is your father self acquired property and hence your son do not have any share in it.