How is the estate of a woman who died leaving behind sons, daughters, and deceased sisters distributed?

The children of sisters (both male and female) are not among the legal heirs; rather, they are considered dhawu al-arham (kindred by blood). Dhawu al-arham do not inherit unless there are no legal heirs whatsoever, neither from the ashab al-furud (sharers) nor from the asabat (agnatic heirs). In such a case, they take the place of the person through whom they are related and inherit their share. In this instance, there is no distinction between male and female in their inheritance, as their inheritance is solely based on kinship.

So, if a woman dies, leaving behind children of full sisters, and no other heirs at all, then all the wealth goes to them. This is because they take the place of their mothers (the full sisters). Full sisters would inherit the entire wealth, two-thirds as a prescribed share (fard) and the remainder by radd (return). The children of each sister would then take their mother's share and divide it among themselves, with the male receiving the same share as the female.

It must be noted that matters of inheritance are complex and cannot be settled by a mere fatwa. Instead, they must be referred to the Sharia courts for investigation into the existence of other heirs, wills, debts, or other rights that take precedence over the rights of the heirs.