Article 15 and begin procedural documentation for a special courts martial. Remove all his numbers, and reduction in rank to Second LT. Provide him his Big chicken Dinner (BCD Bad Conduct Discharge - worse than a dishonorable), and send his sorry butt on his way.
Throw in a stout whipping, five-six years of hard labor, and then one of those ceremonies where you rip off his insignia and break his sword before sending him off in shame and you've got a deal.
I think you are mistaken here. The DD is the worst type of discharge and the most difficult to upgrade by the Board of Review of Corrections of Military Records. BCDs can be given by any court-martial (summary, special and general), but a DD requires a general court martial. DDs are seldom given. BCDs are much more common.
Can't do an article 15(non judicial punishment) and conduct a court martial on the same charges.
He should be tried, convicted, demoted to E-1 then stood against a wall.