"There are four individuals with whom no one else shares inheritance except a husband or wife: the father, the mother, the son, and the daughter. This is the foundational principle for us in matters of inheritance. If a man dies leaving behind his parents, a grandson (son of his son), and a granddaughter (daughter of his daughter), the inheritance is divided between the parents: one-third for the mother and two-thirds for the father. This is because the descendants of children (grandchildren) only inherit in place of the child when there are no direct children or other heirs. In this case, the father and mother are the direct heirs. Al-Fadl ibn Shadhan (may Allah سبحانه وتعالى have mercy on him) held a differing opinion in this matter and erred. He stated that if a man leaves behind a granddaughter through his daughter, a granddaughter through his son, and both parents, then the parents receive one-sixth each, and the remainder is divided: two-thirds to the granddaughter from the son and one-third to the grandson from the daughter. He reasoned that the granddaughter through the son stands in place of her father, and the grandson through the daughter stands in place of his mother. However, this opinion deviates from the correct path and reflects the reasoning of those who rely on analogical deduction (qiyas)."
Commentary #1