Hadith.5634 - Al-Hasan ibn Mahbub narrated from Abdullah ibn Sinan who said
I asked Abu Abdullah (as) about a man who passed away leaving only his maternal brother as an heir and no other inheritor.
Imam (as) said: "The entire estate belongs to him."
I then asked: "What if there is also a grandfather along with the maternal brother?"
Imam (as) replied: "The maternal brother is given one-sixth, and the grandfather receives the remainder."