What is the ruling regarding a wife remaining with her husband who does not wish to return to and cohabit with his first wife, knowing that the first wife is not pleased, and the second wife's mother refuses his return to his first wife? And what should the second wife do, as she fears Allah's punishment and has a child with her husband?

A wife must obey her husband and fulfill his rights. Her husband's return to her is not a reason to seek divorce. Instead, she should advise her husband to be just between his wives in terms of lodging and sustenance, as this is his duty. A wife's waiver of her right to lodging does not negate her right to reclaim it later. As for obeying her mother in what she requested, it is not obligatory, but one should strive to please her with kind words, visits, and gifts.