Clarification in share of father in grand father's property

My grandfather got 2 wives.First wife is my grandmother, who passed away after birth of my father. Second wife is having 5 daughters. Later my grandfather gave very very small portion of property to my father and added he will not have any rights on remaining property. This property is not purchase by my grandfather, it is inherently came. My grandfather died in 1993. In 2017 my grandfathers second wife dead. Now as a son do my father has a right to get equal share in property alongwith his 5 step sisters?