Do grandchildren whose father died before their grandparents inherit a portion of their grandparents' wealth, or does one who dies before his inheritor have no right to inheritance, and what is the legitimate and legal ruling on this in Islamic Sharia and Egyptian law?

If the questioner's father died before his grandfather, he has no right to his grandfather's inheritance, because whoever dies first does not inherit from whoever remains alive after him. However, if the questioner's father left an inheritance, then the questioner and his sister have the right to claim their share of their father's inheritance, and their grandfather is not permitted to deny them their right. The inheritance of the deceased father is divided as follows: one-sixth for his father, one-sixth for his mother, one-eighth for his wife, and the remainder for his children, with the male receiving the equivalent of the share of two females.