It is narrated from Ibrahim (may Allah have mercy on him) that Sayyiduna Abdullah (may Allah be pleased with him) used to make the grandfather share with the brothers down to a third. If a third was better for him (than sharing), he gave him a third. He gave every holder of a fixed share his share. He did not make a maternal brother or sister inherit alongside the grandfather, nor did he count a paternal brother in sharing against a full brother, nor did he make a nephew inherit alongside the grandfather. When there was a full sister, a paternal brother and a grandfather, he gave the full sister a half and the grandfather a half, and gave the brother nothing. When there were brothers, sisters and a grandfather, he gave every holder of a fixed share his share; then if a third of the remainder was better for him than sharing, he gave him a third of the remainder, and if sharing was better for him, he shared. If a sixth of the whole estate was better for him than sharing, he gave him a sixth, and if sharing was better for him than a sixth, he shared.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الفرائض / 12442