How is an inheritance divided among two uterine sisters, and among the heirs are the deceased half-sister's children (sons and daughters) from the father's side, and the deceased half-brother's children (sons and daughters) from the mother's side?

The children of a sister, and the children of a maternal uncle, are not heirs. If the deceased leaves no heirs except for his two maternal sisters, they inherit one-third as a prescribed share, according to the verse: (But if there are more than that, they share in one third). The remainder is returned to them, according to the Prophet's saying (peace be upon him): "Whoever leaves wealth, it is for his heirs." So the inheritance is divided into two shares, one share for each sister, as both a prescribed share and a return. Inheritance cases must be referred to the Sharia courts for investigation, as there might be another heir, or bequests, or debts that take precedence over the rights of the heirs.