Musnad Ahmad 3361

It was narrated that ’Ikrimah said: Ibn ‘Abbas (رضي الله عنه) said concerning the (share of inheritance of the) grandfather: As for the one to whom the Messenger of Allah (ﷺ) said, “If I were to take any one among this ummah as a close friend, I would have taken him as a close friend (i.e., Abu Bakr)," he ruled that he should be given the share of the father (if the father is dead).