Sayyiduna Anas bin Malik (may Allah be pleased with him) narrates that the Prophet (peace and blessings be upon him) said: "Part of righteousness is that you treat your father's friend well."
Al-Tabarani recorded it in al-Mu'jam al-Awsat. Its chain contains a narrator, Anbasah bin Abd al-Rahman al-Qurashi, who is matruk (abandoned).
Sayyiduna Abdullah bin Umar (may Allah be pleased with them both) narrates that the Prophet (peace and blessings be upon him) said: "Preserve your father's friendships! Do not sever them, or else Allah Almighty will extinguish your light."
Al-Tabarani recorded it in al-Mu'jam al-Awsat, and its chain is hasan (good).