The people of Kufa sent a letter to Ibn Az-Zubair, asking about (the inheritance of) (paternal) grandfather. He replied that the right of the inheritance of (paternal) grandfather is the same as that of father if the father is dead) and added, "Messenger of Allah ﷺ said, ' If I were to take a Khalil from this nation, I would have taken him (i.e. Abu Bakr).
قَالَ رَسُولُ اللَّهِ ﷺ لَوْ كُنْتُ مُتَّخِذًا مِنْ هَذِهِ الأُمَّةِ خَلِيلاً لاَتَّخَذْتُهُ أَنْزَلَهُ أَبًا يَعْنِي أَبَا بَكْرٍ