Is a mother's waiver of a waqf invalid if it was made under duress and threat, and not in the presence of a judge, given that she is illiterate, and does this waiver prevent her children from inheriting?

The question addresses two matters:

1. If the mother properly waives her right to the usufruct of the endowment, this does not nullify the right of other classes of descendants, as long as the endower has stipulated their inclusion. 2. If the mother's waiver was due to coercion or deception, it is not considered valid, and the matter should be brought before the judiciary.