Maliks Muwatta Book 027, Hadith Number 000D.

Section : Inheritance of Maternal Half-Siblings.

Malik said, "The generally agreed upon way of doing things among us is that maternal half-siblings do not inherit anything when there are children or grandchildren through sons, male or female. They do not inherit anything when there is a father or the father's father. They inherit in what is outside of that. If there is only one male or female, they are given a sixth. If there are two, each of them has a sixth. If there are more than that, they share in a third which is divided among them. The male does not have portion of two females. That is because Allah, the Blessed, the Exalted, says in His Book, 'If a man or woman has no direct heir, and he has a brother or sister, by the mother, each of them has a sixth. If there are more than two, they share equally in a third.'" (Sura 4 ayat 12).