Is it permissible for the grandmother to retract her gift from the project's profits to her deceased son's children and to demand her share of the money that his widow concealed, knowing that she had verbally relinquished it at the time of death?

If the grandmother renounces her right to inheritance or donates her share, she is not permitted to retract it, as retraction of a gift is forbidden, except for a father regarding what he gives to his child. However, if she did not explicitly donate her share, but rather was giving her grandchildren from the profits, she is not obligated to continue doing so. The grandmother has the right to demand her share of the amount that was concealed from her, because her renunciation was based on the known inheritance, not the unknown, and concealing it is an injustice. A settlement regarding an unknown amount that can be ascertained is not valid.