a single full or paternal brother or sister, the grandfather receives one-half of the estate. With two brothers he takes one-third; with two sisters he again takes one-half; with one sister he takes two-thirds; with three sisters he takes two-fifths; and the same calculation applies when there is a brother and a sister together. If there are four sisters, his share is one-third.

On this basis, whenever the only other heirs are brothers and sisters and no one entitled to a fixed share is present, the grandfather shares with one brother, or with two, three, or four sisters, or with one brother and one sister. If the number of siblings exceeds these limits, the grandfather is entitled to a full one-third of the estate, undiminished, and whatever remains goes to the brothers and sisters.

If, however, someone entitled to a fixed share (dhū ʾl-sihām) is present, that person is first given his or her allotted portion, after which the grandfather is awarded whichever of the following three options is most advantageous for him: (1) one-sixth of the entire estate, (2) an equal share with the siblings in what remains, or (3) one-third of what remains after the fixed portions have been distributed. He is given whichever of these three yields the larger amount.

The fixed-share heirs include, for example, the husband, wife, mother, grandmother, daughters, and granddaughters through a son. If there is only one such heir and his or her prescribed share is one-half or less, the fixed shares are paid first; then the grandfather shares the residue with one sister, or with two, three, or four sisters, or with one brother and one sister, taking an amount equal to the share of a single brother and the share of a single sister, for he is treated as one of the siblings. Should their number exceed these limits, the grandfather receives one-third of the residue, and the balance is distributed among the brothers and sisters, with a male receiving the share of two females.

If the prescribed share exceeds one-half but does not reach two-thirds, the grandfather shares with one sister, with two sisters, or with one brother; but if the siblings are more than this, the grandfather is limited to one-sixth. And if the total of the fixed shares surpasses two-thirds, the grandfather is allotted a fixed one-sixth of the entire estate, and whatever remains goes to the brothers and sisters, the male receiving the portion of two females.