How should one act regarding the charity sent by a friend who passed away before specifying its recipient or address?

Most scholars are of the view that charity is not binding except upon قبض (seizure/possession). Accordingly, the aforementioned charity did not leave the possession of the giver because قبض (seizure/possession) did not occur. Therefore, the charity must be returned to the heirs of the deceased, as it is part of his estate.