Great grand father's property division

My great grand father bought a property in 1960. He had 2 sons and 1 daughter. He made a will in 1996 which is registered in favour of my grandfather's brother. My great grand father also made another will which is notarised in 1999 in favour of my grandfather. He died in 1999. My grandfather's brother moved out of the house and shifted to another city in 1991; however my grandfather, my father and I have been living in the same house since birth. Now my grandfather passed away recently and my grandfather's brother is asking us to sell the property stating he has registered will. We don't want to sell the property. Please suggest as to what should be done?