Musannaf Ibn Abi Shayba 26:501

Waki’ narrated to us, he said: Sufyan narrated to us, from Ibn Jurayj, from ‘Ata’, regarding a man who died and left behind a freedman (mawla) of his, his grandfather, and his brother: To whom does the wala’ (right of inheritance/patronage) of his freedman belong? ‘Ata’ said: The wala’ is between them in two halves.