Is it permissible for a childless widow to donate her share of her deceased husband's inheritance to his daughter?

A woman's donation of her share of inheritance to her husband's daughter is Islamically valid if the donor is competent to dispose of property. For the donation to be effective, the donee, or whoever is responsible for her affairs, must take possession of the donated item. For the donation to be valid, it must meet its conditions, which include the donor relinquishing control over the donated item and the daughter or her representative taking possession of it.