What is the share of a son from his father's inheritance if the son died before him, and he (the son) has three brothers and two sisters, and knowing that the son's mother is deceased?

May Allah have mercy on your father, grandfather, and grandmother and grant them forgiveness. If your grandfather passed away, leaving behind a wife, four sons (one of whom is your father), and two daughters, then the wife receives one-eighth (1/8) due to the presence of a lineal descendant, as Allah Almighty says: "But if you have a child, then for them is one eighth of what you leave." The remainder is divided among the sons and daughters, with the male receiving the share of two females. The inheritance is divided into 80 shares: the wife receives 10 shares, each son receives 14 shares, and each daughter receives 7 shares. Thus, your father's share is 14 shares out of the original 80 shares. Your father does not inherit from his mother if she passed away before him.