If a house is endowed (waqf) for one’s children and they all die during the lifetime of the person who…

Answer

In the name of Allah, if the waqf is restricted solely to the children without any intermediary, the waqf is not valid, because continuity is a condition of the waqf as long as the world and its people exist, and the waqf is only valid for the children and their descendants. If the endower’s lineage ends; no sons, daughters, grandchildren, or other descendants such as grandsons, the waqf becomes invalid. Allah knows best.