Musannaf Ibn Abi Shayba 26:227

Ibn Fudayl narrated to us, from Bassam, from Fudayl, who said: Ibrahim said regarding a man who left behind his grandfather, his sister (full-blood), and his brother (paternal): In the judgment of Zayd, the grandfather receives two-fifths out of ten, which is four shares. The full-blood sister receives the half, which is five shares. The paternal brother receives one share. The brother (paternal) in the judgment of Zayd and Ali—and the full-blood sister used to have three-fifths of the wealth, but she was given the half because three-fifths is more than the half, and the single sister does not have more than the half if she divides with him. Abdullah used to give the full-blood sister the half and the grandfather the half, and he would not count the paternal siblings, nor would he have the full-blood sister divide with them. Ali used to assign the full-blood sister the half, and he would assign the [remaining] half between the brother and the grandfather, with the grandfather being like one of them, as long as the grandfather’s portion was not less than one-sixth. If one share remained, and if there were two brothers, then the half is between them. Abu Bakr said: This, according to the view of Zayd, is out of ten shares; and according to the view of Abdullah, it is out of two shares; and according to the view of Ali, it is out of four shares. And Ali makes it out of six when the siblings are numerous.