If the property of the grand father was his self acquired property then this property shall devolve to all his legal heir if he died intestate i.e. no testamentary document such as 'will' exist with regard to the property made by him during his life time. The grandson is not legal heir if his father is alive in such case, in case the father of the grandson died before the death of grand father then the grandson being son of the predeceased son get the share in the property which his father would have got, sharing that share along with his mother i.e. widow of his father. In this case there are 1 son of the grand father, no mention of his widow hence these all being class 1 Heir get one share each in this property. This the position based on the Hindu Succession Act, 1956. The grandson could gave got his share in the property if that was Hindu Ancestral Property, i.e. originally owned by the great grand father, passed to the grand father down the line up to the present grandson who would be the fourth generation to enjoy this property, in this case in this Hindu undivided family property a share could be claimed by the present grandson being a Coparcener by birth in the Hindu Joint family. Whatever I state here is based on the actual legal position concerning the Hindus in India & if this doesn't make you feel happy then I'm sorry its not my fault as one idiot NRI who wanted to get share in his grand father's property & I told him it was not possible got annoyed with me for not fault of me. I can only tell what present law says, neither this law was drafted by me nor I can state wrong legal position just to make the asker happy with this wrong information which other lawyers/advocates maybe doing here.