How is inheritance distributed among a mother, a daughter, a granddaughter (daughter of a son), and a great-granddaughter (daughter of a son's son)?

If the heirs are limited to those mentioned, then the son's daughter is excluded by the two daughters.

The heirs are: the mother, who receives one-sixth; the daughter, who receives one-half; and the son's daughter, who receives one-sixth to complete the two-thirds.

The inheritance is divided into 5 shares: one share for the mother, 3 shares for the daughter, and one share for the son's daughter.

It must be noted that matters of inheritance are serious and must be referred to the Sharia courts for investigation and consideration of wills, debts, and other rights before division.