What is the ruling on the maintenance of a wife by an imprisoned or absent husband?

The maintenance of the wife of a prisoner, a missing person, or an absent person whose news has been cut off, is obligatory upon her husband. The waiting period is four years. If the husband has wealth, he should spend from it on his wife and children. If his death becomes apparent during this period, then what the wife spent after his death shall be refunded from the inheritance, and she will take her lawful share.