Is expiation obligatory upon one who swore not to take his children to a specific place as a punishment for them, and then their grandfather went and brought them to that same place?

If the swearer intended by her oath not to take the children to their grandfather herself, and did not intend to prevent them from going with him by someone else, then she does not break her oath if the father brings them, because the oath is based on the intention of the swearer. However, if she intended to prevent them from going to him on that day in any way, then she breaks her oath if the father brings them and is required to offer expiation for the oath. If the father's satisfaction is in their being brought, then breaking the oath is better in this case, based on the saying of the Prophet, peace and blessings be upon him: "Whoever swears an oath and then sees something better than it, let him do what is better and offer expiation for his oath."