Umar bin al-Khattab (may Allah be pleased with him) consulting about the inheritance of the grandfather and brothers

It is narrated from Sayyiduna Ma'qil bin Yasar (may Allah be pleased with him) that Sayyiduna Umar (may Allah be pleased with him) asked: "Does anyone have a saying of the Messenger of Allah (peace and blessings be upon him) concerning (the inheritance of) the grandfather?" I said: I have. He asked: What is it? I said: He (peace and blessings be upon him) gave him one-sixth (1/6). He asked: "Along with whom (among the other heirs)?" I said: I do not know. So he said (in regret): "Then may you never know."
This hadith is sahih (authentic) on the condition of the two Shaykhs (Bukhari and Muslim), but they did not record it.

It is narrated from Sayyiduna Ibn Abbas (may Allah be pleased with them both) that Sayyiduna Abu Bakr al-Siddiq (may Allah be pleased with him) treated the grandfather as standing in the place of the father (in matters of inheritance) (that is, in the absence of the father, he inherits like the father).
This hadith is sahih (authentic) on the condition of the two Shaykhs (Bukhari and Muslim), but they did not record it.

Kharijah bin Zayd bin Thabit narrates from his father that when Sayyiduna Umar bin al-Khattab (may Allah be pleased with him) consulted the Companions concerning the inheritance of the grandfather and the brothers, Zayd said: My view was that the brothers have a greater right to the inheritance than the grandfather, whereas Sayyiduna Umar (may Allah be pleased with him) held the view at that time that the grandfather has a greater right to the inheritance of his grandson than the grandson's brothers. Zayd said: "I discussed this with Sayyiduna Umar (may Allah be pleased with him) and presented an example before him to clarify the matter; and Sayyiduna Ali bin Abi Talib and Sayyiduna Abdullah bin Abbas (may Allah be pleased with them) also presented before Sayyiduna Umar (may Allah be pleased with him) that day the example of a flowing flood, and they would present this example and apply it in the same way that Zayd had applied it."
This hadith is sahih (authentic) on the condition of the two Shaykhs (Bukhari and Muslim), but they did not record it.

It is narrated from Urwah bin al-Zubayr that Marwan bin al-Hakam told him that when Sayyiduna Umar (may Allah be pleased with him) was stabbed, he said: "I have formed an opinion concerning the inheritance of the grandfather; if you see fit, then follow it." At this Sayyiduna Uthman (may Allah be pleased with him) said: "If we follow your opinion, it is entirely right guidance; and if we follow the opinion of the elder before you (Sayyiduna Abu Bakr al-Siddiq, may Allah be pleased with him), then what an excellent man of opinion he was."
This hadith is sahih (authentic) on the condition of the two Shaykhs (Bukhari and Muslim), but they did not record it.