What is the basis for granting the grandfather priority over siblings?
Chapter on Inheritance of the Grandfather
Al-Mughni
Book of Inheritance Shares (Farā'id)
Primary text
The priority of the grandfather over siblings is derived from the prophetic statement: 'Return the fixed shares to their owners, and whatever remains belongs to the nearest male 'asabah.' The grandfather is nearer than the sibling due to his relationship of procreation (ilad) and partial parentage, similar to the father. Evidence supporting this includes that when fixed shares conflict, the sibling is veiled while only the father veils the sibling, and the grandfather shares with siblings in receiving both a fixed share and residuary portion like the father. Additionally, the grandfather is equated to the father in rulings such as not being subject to retaliation for killing his grandson, not being subject to Hadd punishment for slandering his grandson's wife, and being exempt from receiving Zakat.
Supporting text
The argument for the siblings inheriting alongside the grandfather is based on the Quranic establishment of their shares, necessitating proof for their exclusion. Furthermore, they share an equal right through the father, where the grandfather is the father's father and the sibling is the father's son, suggesting the son's relation is not necessarily weaker than the father's relation.