Does the mother of a son who died during his father's lifetime inherit her son's share of his father's estate, or not?

A son who dies before his father does not inherit from him, as one of the conditions for inheritance is the life of the heir at the time of the deceased's death.

If the deceased left no one but those mentioned, then his wife receives one-eighth due to the presence of inheriting offspring. Allah states: "But if you have a child, then for them is one-eighth of what you leave, after any bequest you [may have] made or debt."

The remainder goes to the sons and daughters by virtue of ta'sib (agnatic inheritance), with the male receiving the share of two females. Allah states: "Allah instructs you concerning your children: for the male, what is equal to the share of two females."

The amount (750,0) is divided into eighty-eight shares: the wife receives eleven shares (93,750), each son receives fourteen shares (119,318), and each daughter receives seven shares (59,659).