Ata' (may Allah have mercy on him) related that Sayyiduna Abu Bakr (may Allah be pleased with him) used to say: "The grandfather is like the father when there is no father, just as the son's son is like the son when there is no son."
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الفرائض / 12281
It is reported from Sa'id bin al-Musayyab (may Allah have mercy on him) that Zayd bin Thabit (may Allah be pleased with him) would not assign a share to the grandmother when her son, that is, the father of the deceased, was present.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الفرائض / 12282
It is narrated from Imam al-Sha'bi (may Allah have mercy on him) that Sayyiduna Ali and Sayyiduna Zayd (may Allah be pleased with them both) both did not assign any share of the inheritance to the grandmother when her son (the father of the deceased) was present.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الفرائض / 12283
It is narrated from Ibrahim that Sayyiduna Ali and Sayyiduna Zayd bin Thabit (may Allah be pleased with them both) did not make the grandmother an heir in the presence of her son.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الفرائض / 12284
Al-Zuhri (may Allah have mercy on him) said that Sayyiduna Uthman (may Allah be pleased with him) would not make the grandmother an heir alongside her living son.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الفرائض / 12285
It is reported from Sayyiduna Abdullah (may Allah be pleased with him) concerning the grandmother whose son is present: the first grandmother to whom the Messenger of Allah (peace and blessings be upon him) gave a sixth was given it while her son was also alive.
Muhammad bin Salim is alone in narrating it this way. It has also been narrated from Yunus from Ibn Sirin, who said: "I was informed," and from Ash'ath bin Sawwar from Ibn Sirin from Abdullah, and from Ash'ath bin Abd al-Malik from al-Hasan and Ibn Sirin from the Prophet (peace and blessings be upon him). The hadith of Yunus and of Ash'ath is munqati' (its chain is broken), and Muhammad bin Salim is not relied upon as evidence; the authentic narration on this is only from Umar, Abdullah and Imran bin Husayn.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الفرائض / 12286
Sa'id bin al-Musayyab (may Allah have mercy on him) said that Sayyiduna Umar bin al-Khattab (may Allah be pleased with him) made the grandmother of a man from Thaqif an heir in the presence of her son.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الفرائض / 12287