Muhammad b. ‘All b. Husain quoted ‘Ali b. Abu Talib as saying that God’s messenger sacrificed a sheep on the seventh day for al-Hasan and said, “Shave his head, Fatima, and give the weight of his hair in silver as sadaqa.” So they weighed it and it amounted to a dirham or part of a dirham.
Tirmidhi transmitted it, saying this is a hasan gharib tradition, but its isnad is not fully connected because Muhammad b. ‘Ali b. Husain was not born in the time of ‘Ali b. Abu Talib.