What is the ruling on the grandmother taking her share of the blood money after she has waived it?

This waiver is a type of gift, and the original ruling regarding retraction of a gift is that it is forbidden, based on the Prophet's (peace be upon him) saying: "The one who retracts his gift is like a dog that vomits and then returns to its vomit."

However, scholars have differed on two issues related to the question:

1. Ruling on the grandmother retracting a gift: Most scholars hold that the grandmother does not have the right to retract a gift. 2. The donor retracting a gift before the donee takes possession: Most scholars hold that the donor may retract the gift before the donee takes possession of it, because ownership is not established except by possession, according to the Hanafis, Shafi'is, and some Hanbalis.

Therefore, it is not permissible for the grandmother to retract her waiver of her son's blood money for her grandchildren, unless her retraction was before the grandchildren took possession of their share of the blood money, in which case she may retract.