Is a son considered undutiful to his parents if he brings his wife to live with him in his country of expatriation and only visits his family during annual holidays, while committing to their monthly expenses and those of his brother, due to his mother's ill-treatment of him and his wife?

It is permissible to bring your family to live with you if your parents do not need you and are not harmed by it. Obedience to parents is obligatory in what is good and known, and it is not considered good or known for them to prevent you without harm, and disobeying them in this case is not considered disobedience ( 'Uquq). You must strive to honor them and earn their رضا (contentment), especially your mother, and be patient with her jealousy towards your wife.