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