Unfortunately he should have appealed the Article 15 at the time. It is most likely not appealable at this time. The only recommendation I have is to talk to the chain of command from the Company Level through the BDE Level. You can check with JAG as well for their thoughts. I sincerely believe the only option available to your husband is that he must appeal to have his article 15 fully set aside by the chain of command or appeal to the board of Military corrections. Check AR 27-15 on the procedures for wholly setting aside of an article 15.