The Kitáb-i-Aqdas - The Most Holy Book
Index term: grandchildren, under allocation of shares and property; Inheritance
k26.
Should the son of the deceased have passed away in the days of his father and have left children, they will inherit their father's share, as prescribed in the Book of God. Divide ye their share amongst them with perfect justice. Thus have the billows of the Ocean of Utterance surged, casting forth the pearls of the laws decreed by the Lord of all mankind.
n45.
Should the son of the deceased have passed away in the days of his father and have left children, they will inherit their father's share
This aspect of the law applies only in the case of the son who predeceases his father or mother. If the daughter of the deceased be dead and leave issue, her share will have to be divided according to the seven categories specified in the Most Holy Book (Q&A 54).