He was asked about the case of a husband and a sister from the same mother and father. He gave the husband half and the sister half. When he was questioned about this, he said, "I was present when the Messenger of Allah ﷺ ruled in this manner."
حدثنا الحكم بن نافع حدثنا أبو بكر بن عبد الله عن مكحول وعطية وضمرة وراشد
أنه سئل عن زوج وأخت لأم وأب فأعطى الزوج النصف والأخت النصف فكلم في ذلك فقال حضرت رسول الله ﷺ قضى بذلك
No references are available.
Its chain of transmission is daif because of Abu Bakr bin Abdullah bin Abu Jahm. As for those from whom he narrates, they are all trustworthy and well known. Makhul is Shami, Atiya is Ibn Qays, Damra is Ibn Habib, and Rashid is Ibn Saad. Haythami mentioned the hadith in 4/228 and graded it daif because of Abu Bakr.