Is the son considered sinful towards his mother if he refuses to marry a woman he does not desire, especially since his mother mistreats his wife and children and pressures him to marry another?

Obedience to the mother is not obligatory in marrying someone the son does not desire or divorcing his wife. If the mother mistreats her son's wife, he should gently advise her. There is no obedience to her if she prevents him from housing his wife in a separate dwelling if she is subjected to harm, as the wife is not obligated to live with her husband's mother. It must be noted that honoring the mother is obligatory, regardless of what she does.