Is it permissible for a husband to briefly visit his sick mother during an episode of his other wife, who does not live with the mother-in-law?

It is permissible for a husband to visit his second wife during the day for a need, such as to check on her or to deliver sustenance. He may also enjoy her company, excluding intercourse, without prolonging his stay. However, at night, it is not permissible unless there is an extreme necessity. As for the husband leaving to visit his sick mother, it is permissible both day and night, provided that the visit is limited to the extent of the need, after which he should return to his other wife.