What is the ruling on a gift contingent upon the marriage of the donee if the donor dies, and the donee takes possession of it after the donor's death, and does the heir have the right to reclaim it?

If the donor dies before the donee takes possession of the gift, the gift becomes void. The donee's taking possession after the donor's death is considered an encroachment upon the heirs' property, and they have the right to reclaim it. However, if the heirs, being mature and of sound judgment, hand over the gift to the donee, it is considered a new gift from them and becomes binding. They do not have the right to revoke it, based on the Prophet, peace and blessings be upon him, who said: "It is not permissible for anyone to give a gift and then take it back, except for a father in what he gives to his child," and his saying: "The one who takes back his gift is like a dog that vomits and then returns to its vomit."