‘Ali said

You recite this verse, “After a legacy you bequeathe or a debt (Al-Qur’an 4:12),’’ but Allah's Messenger ﷺ decided that a debt should be discharged before a legacy and that the sons of the same mother inherit from one another, but not the sons of one father by different mothers. A man inherits from his brother who has the same father and mother, but not from his brother who has the same father but a different mother. Tirmidhi and Ibn Majah transmitted it. In a version by Darimi he said, “Brothers who have the same mother inherit from one another but not sons of the same father but of different mothers, etc."