Musannaf Ibn Abi Shaybah 33485 — Three who drowned while their mother

Ibrahim reports that Sayyiduna Ali (may Allah be pleased with him) made three men who had drowned while travelling in a boat heirs of one another while their mother was alive, and he made their mother heir to one sixth from each of them. Then, of the inherited wealth that he gave each of these brothers from the other, he gave one third to the mother, and he gave the remaining wealth to the agnates (asabah).