The person about whom Messenger of Allah ﷺ said, "If I were to take a Khalil from this nation (my followers), then I would have taken him (i.e., Abu Bakr), but the Islamic Brotherhood is better (or said: good)," regarded a grandfather as the father himself (in inheritance).
قَالَ رَسُولُ اللَّهِ ﷺ لَوْ كُنْتُ مُتَّخِذًا مِنْ هَذِهِ الأُمَّةِ خَلِيلاً لاَتَّخَذْتُهُ وَلَكِنْ خُلَّةُ الإِسْلاَمِ أَفْضَلُ أَوْ قَالَ خَيْرٌ فَإِنَّهُ أَنْزَلَهُ أَبًا أَوْ قَالَ قَضَاهُ أَبًا
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
[Machine] The translation of the given Arabic phrase into English is: The messenger of Allah ﷺ said, "If I were to take a close friend from this nation, I would have chosen Abu Bakr, as he is like a father to me."
لَهُ رَسُولُ اللهِ ﷺ لَوْ كُنْتُ مُتَّخِذًا مِنْ هَذِهِ الْأُمَّةِ خَلِيلًا لَاتَّخَذْتُهُ فَإِنَّهُ قَضَاهُ أَبًا يَعْنِي أَبَا بَكْرٍ