Do the daughters' children inherit anything from their grandfather's estate if their mother died during her father's lifetime, and then the father died?

There are three conditions for inheritance: the actual death of the deceased or their legal equivalent, the actual life of the heir after the deceased or their legal equivalent, and knowledge of the heir's relation and how they are connected. A daughter is inherited by her father, and her children have no right to inherit from their grandfather except through a will not exceeding one-third, or more than one-third with the permission of the heirs.