Musannaf Ibn Abi Shaybah

Ibrahim narrates that Hazrat Zaid (may Allah be pleased with him) used to make the grandfather an heir up to one third of the wealth along with brothers and sisters. So when his share reached up to one third, he would grant him one third, and the remaining wealth would belong to the brothers and sisters. And in the presence of the grandfather, he would not give anything to maternal brothers and maternal sisters. And he would include paternal brothers in the division with full brothers, but would not grant anything from the inheritance to the paternal brothers. So if a full sister and the grandfather were heirs, he would grant half of the wealth to the grandfather, and if there were two brothers, he would grant one third of the wealth to the grandfather. So if there were more brothers, he would grant one third of the wealth to the grandfather and the remaining wealth to the brothers. And when one sister and the grandfather were heirs, he would grant two thirds of the wealth to the grandfather and one third to the sister. And if there were two sisters, he would grant half of the wealth to the sisters and half to the grandfather, provided that such mutual division was better for the grandfather. So if along with them, other heirs such as the wife, mother, and husband had shares, he would first grant those heirs their shares and then divide the remaining wealth among the brothers and sisters. In this way, if one third of the remaining wealth was better for the grandfather, he would grant him one third of the remaining wealth, and if mutual participation in the division was better for him, he would do so. And if one sixth of the entire wealth was better for him than participation in the division, he would grant him that, and if participation in the division was better for the grandfather than more than one sixth, he would include him in the division.