What is the ruling on dividing a grandfather's relinquishment of his share to his deceased son's children (the siblings of the deceased) after his death? Is it "to the male, a portion equal to that of two females" or according to the number of heads?

The grandfather, along with the Ashab al-Furud (sharers) and full or paternal siblings, takes the best of three options available to him: one-sixth of the estate, or the remainder after the sharers have taken their shares, or a muqasamah (sharing) with the siblings.

If the grandfather relinquishes his share in favor of some of the heirs, then if a method of distribution is specified, it should be followed. Otherwise, it is to be divided equally among them.

It is advisable to refer inheritance matters to the Sharia courts for investigation and to ensure that there are no wills, debts, or other rights that take precedence over the rights of the heirs.