Is the husband sinful for preventing his wife from accompanying her sick mother? Is obedience to him obligatory in this regard? And is the wife sinful for remaining in this marriage, knowing that she wears a modest hijab and does not speak to men, and that her husband justifies his prevention by fearing for her from societal harassment?

There is no sin upon you for remaining with your husband despite your mother's disapproval. It is obligatory upon you to obey your husband if he forbids you from going out with your mother to the market or similar places. He has the right to prevent you from going out unless there is a necessity. This is supported by what Al-Bukhari and Muslim narrated from Ibn Umar, that the Messenger of Allah (peace be upon him) said: "Do not prevent the female servants of Allah from Allah's mosques."

Al-Baji said: "'Do not prevent the female servants of Allah from Allah's mosques' is evidence that the husband has the right to prevent them from that, and that they should not go out except with his permission."

If your husband's command and your mother's command regarding going out conflict, then you must obey your husband. You will not be disobedient to your mother in such a case.

Ibn Taymiyyah said: "When a woman marries, her husband has more authority over her than her parents, and obeying her husband is more obligatory upon her." Al-Mardawi said: "She is not obligated to obey her parents in separating from her husband, nor in visiting them or similar matters; rather, obedience to her husband is more rightful."

We advise your husband to assist you in honoring your mother and to permit you to go out with her for her needs if there is no harm in it.