Share for first wife's son

Hi Sir, I am Hindu i am 23yrs old girl I have a question regarding my dad's father's Property My grandfather has two wife's my dad is first wife's son when his mother was alive only my grandfather married again and had children also my grandfather put my dad out of house when he was 7-8yrs old my dad's mom also expired when he was 7yrs old so my dad was alone. my grandfather also passed away after many years (in 1999) after my grandfather passed away no one gave my dad's share. my dad grew in Bangalore alone as a orphan my dad is 51 now,can my dad get his share on his father property as he is first wife's son (only son) he has still not gone to that village to ask for anything,whatever my grandfather got from ancestral and also his earnings both second wife's children have not given anything to my dad 1)can we put a case on them for property? 2)will my dad not get anything because my grandfather passed away long back? 3)will my dad a share on his fathers property please ans mee.....