1) on your grand father death your father has 1/4th share in house .
2) if your aunts have no interest in the house they can execute deed of relinquishment or gift deed in your father favour .
3) enter into deed of partition with your uncle .for division of house by metes and bounds .
4) once your aunts execute gift deed in your father favour your uncle will have only 1/4th share in the house .