Is it permissible to distribute one-third of the deceased's estate, bequeathed for charitable purposes, equally among the heirs for each to distribute it according to their own discretion, and what is the difference between charitable work and an endowment (waqf)?

If a father bequeaths to specific individuals equally, then the one-third (of his estate) is divided among them in the same manner. However, if the bequest is generally for charitable acts, it is better to make it an endowment (waqf) that generates profits to be spent on good causes, based on the Prophet's (peace be upon him) saying: "When a person dies, all his deeds come to an end except for three: ongoing charity (ṣadaqah jāriyah), knowledge from which others benefit, or a righteous child who prays for him." The ongoing charity is the endowment (waqf), and this is what the Prophet (peace be upon him) guided Umar ibn al-Khattab (may Allah be pleased with him) to do. An endowment (waqf) is the retention of the principal and the dedication of its usufruct (benefit), whereas charitable acts are more general, encompassing endowments and other forms of charity and spending.