Is the wife obligated to remain in her in-laws' home to serve her husband's psychologically ill mother, despite the ill-treatment of her husband's brother and her fear for her husband of being undutiful to his mother if she leaves the home?

It is the wife's right to have an independent dwelling, and this does not constitute disobedience to the husband's mother. The mother's maintenance and service are obligatory upon her husband; if he is poor, then upon her children, and they should compete in honoring her. The brother should also be advised on ways to manage anger to avoid its negative consequences.