I don't know the exact terms for the documents you should provide as I'm not algerian but from what I have seen elsewhere (whatsapp groups, facebook groups forums etc) You need to have a yellow card (Carte jaune) / "Carte de situation" ? Anyway you have to ask the military administration for a document relieving your husband from this duty.Do you have any information about the documents that we should prepare please ?
(My husband which is the dependent didn't do the military service (we're from Algeria and It's mendatory here) but he still didn't receive any invitation from military services to do it.)