Kharijah bin Zayd (may Allah have mercy on him) narrates from his father (Sayyiduna Zayd bin Thabit, may Allah be pleased with him) that he said: The father's inheritance is from his son or daughter if he (the child) dies. If the deceased leaves male offspring or grandsons, the father's fixed share is a sixth. If the deceased has no male offspring and no grandsons, the father will be deferred, and the people of fixed shares will first be given their shares. If more than a sixth of the wealth remains, it will be the father's; if no more remains, only a sixth will be the father's.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الفرائض / 12334