Partition advise - urgent hep

My brother is selling the house, which is under name of my grandfather which is self acquired by him for 1 lac around 1980's. My grand father and my father has been deceased. For my mother sake, i am buying the house by paying full price to my brother and he doesn't want to pay his IT for the cash received i want to do registration in my name and we have been advised go for partition deed approach saying brother took family cash (which is my cash paid amount) and house belong to me. My question, 1.In future, if i sold this property does i have to pay capital again from 1980's or happening from partition deed time? 2. If i am going through partition deed approach, in future does it create any complication while selling or my brother family can claim the rights? Please advise?