Musannaf Ibn Abi Shayba 26:503

Zayd ibn al-Hubab narrated to us, from Ibn Abi Dhi’b, from al-Zuhri, regarding a man who left behind his grandfather and his brother: He said: The *wala’* (patronage/right of inheritance) belongs to the grandfather, because he is attributed to the grandfather and is not attributed to the brother.