Father wants to transfer his flat or flat sale money only on his son

We are only 2 adult unmarried children (Son 46 yrs and daughter 44 yrs, she is not working) of my father (82 yrs govt retired pensioner) living with him only and mother is expired already. As me and my father have no good relations with his daughter or my sister so my father now only (before his death) wants to transfer his (own money invested) current living flat or after flat sale all money on my (his son) name only and wish to give any to his daughter. So guide me how we can do legal formalities on this issue so in future I will not get any claim related problem from his daughter or my sister?