Is the children's disobedience to their father's command to return to him considered an act of defiance, and must they obey him or their mother, and is it permissible for the father to withhold financial support from them to deter them from their disobedience and their obedience to their mother in matters that are not in their best interest?

If the custodial mother travels, moving permanently from the father's country, her custody is forfeited according to the majority of scholars. However, the Hanafis permit the mother to travel a long distance with the child if it is her hometown where the father married her. If the father consents to their travel with their mother, there is no harm. An adult son has the choice to reside and live independently, and is not obligated to live with his parents. Financial support (nafaqa) is obligatory upon the father for his minor children, and for adult children capable of earning according to the Madhhab of Ahmad, if they do not possess their own wealth. It is commendable for the father to consider the best interests of his children; if their residence in Egypt is more beneficial, he should not be strict with them, and if their remaining near him is more beneficial, he should strive for that.