House in our possession since 1946 uncle claiming share

In 1946, my father had been transaction between my elder grandfather. At that time my father was put my grandmother's name as guardian for my uncle.My father(21) was an elder brother, others were kids n my grandmother was 36-37 yrs old while transaction is done. My father has been 1 bro and 3 sis. My father was maintained record in diary with time of transaction.Now my uncle had put my both unty's name on index. My father was paid for house. Now house's possession is under us since 1946.My uncle had never came to at this home.After death of my father he is demanding his share and others.