“I heard the Prophet (ﷺ) when a case was brought to him which involved the share of a grandfather. He gave him one third, or one sixth.”
Sunan Ibn Majah Book 23, Hadith 4
← Previous Hadith “A man came to Abu Musa Al-Ash’ari and Salman bin Rabi’ah Al-Bahili and asked them about (the shares of) a daughter, a son’s daughter, a sister through one’s father and mother. They said: ‘The daughter gets one half, and what is left goes to the sister. Go to Ibn Mas’ud, for he will concur with what we say.’ So the man went to Ibn Mas’ud, and told him what they had said. ‘Abdullah said: ‘I will go astray and will not be guided (if I say that I agree); but I will judge as the Messenger of Allah (ﷺ) judged. The daughter gets one half, and the son’s daughter gets one- sixth. That makes two thirds. And what is left goes to the sister.’”

Sunan Ibn Majah Book 23, Hadith 3 Next Hadith → “The Messenger of Allah (ﷺ) ruled concerning a grandfather who was among us, that he should receive one sixth.”

Sunan Ibn Majah Book 23, Hadith 5