Can property be claimed after death?

My father sold his property and gave equal shares to each of his children. He bought a flat with his share and I with mine in the same city. Later due to the ill health of my mother we both decided to sell our place and buy a single home. The new house was in my father's name under a power of attorney. My mother died and my father decided to sell off the place and move to another place. He received the initial advance and decided the rest to be accommodated against our new home. Later my father also passed away after signing the full and final agreement. Now my sister is claiming her share. Can she do that?