Ownership issue

Hi, My grandfather bought a land of 2.5 kattha in Bihar. In my GF's will he gave 2 kattha to my father. There is house built in rest of 0.5 kattha. His will says that two of his daughters can live in that house and if sold then money will be divided equally among 4 people me my sister and those two daughters(my fathers's sisters). Land will be sold if my fathers agrees. Now my father is no more and he made no changes. my question is 1. Do i have power to sell the house? 2. Do i have power to live in that house?