Sayyiduna Ibn Abbas (may Allah be pleased with them both) said that the Messenger of Allah (peace and blessings be upon him) said: "If I were to take anyone as a khalil (intimate friend), I would take Abu Bakr (may Allah be pleased with him) as a khalil." It was he (may Allah be pleased with him) who made the grandfather a father.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الفرائض / 12417