What is the ruling on a mother opposing her son's marriage to the one he loves, insisting on marrying him to another, and opposing polygyny, and is the son considered disobedient if he disobeys her in that?

A mother does not have the right to compel her son to marry someone he dislikes, nor to prevent him from marrying someone he loves, unless there is a legitimate Sharia reason. Her obedience is not obligatory in such a matter, due to the harm it would inflict upon the son. If the mother advises against polygyny after her death, there is no sin upon the son for disobeying her. However, if the son would not be harmed by refraining from marrying whom he desires, and the girl his mother wants for him is righteous, then marrying her is more preferable. Similarly, if there is no need for polygyny, then obedience to the mother is appropriate, while striving to show her filial piety and kindness.