Do the children of one of the deceased heirs benefit from the bequeathed commercial endowment (waqf), if the rest of the heirs are still alive?

If a person dedicates his building during his lifetime as an endowment (waqf) for his direct children, excluding others, and stipulates that their children shall not benefit until after the death of their parents, then the endowment is valid. It is not permissible for the children of the deceased to benefit before the death of their uncles.

However, if he dedicates it as an endowment for his children through a will, the endowment is not valid unless the other heirs agree, based on the saying of the Prophet, peace and blessings be upon him: "There is no will for an heir unless the heirs wish it."

But if he dedicates it as an endowment for the children of his children through a will, it is permissible because they are not heirs while their parents are alive.