What is the ruling when a brother acknowledges a full brother?
Chapter on Distant Kindred (Dhawu al-Arham)
Al-Mughni
Book of Inheritance Shares (Farā'id)
Primary text
If a brother acknowledges a full brother, the acknowledged brother receives three-eighths of what is in the hand of the acknowledging brother. This is because the acknowledgment scenario is based on twelve parts, to five of which the acknowledging brother is entitled, while eight parts are in his possession, leaving a surplus of three parts which go to the acknowledged brother.