What is the share of each of the two daughters from their mother's inheritance, which she received from her son who died before her?

The male heirs are fifteen, and the female heirs are ten. The method of distributing the inheritance cannot be explained until the heirs are precisely identified.

If it is assumed that the grandmother left behind only her two daughters and her son's children, then her two daughters receive two-thirds, and the remainder goes to the son's children by ta'sib (residuary inheritance). The share of the deceased daughter transfers to her heirs.

Given the gravity and complexity of inheritance matters, one should not be content with this answer alone. The issue should be referred to the Sharia courts or consulted with scholars to ascertain the heirs and to confirm the existence of any wills, debts, or other rights that take precedence over the heirs' rights.