Bottom Line Up Front (BLUFF): The command CANNOT extend a Soldier past their ETS date for an administrative separation. The command can only extend a Soldier past their ETS if they intend to take the Soldier to Court-Martial. I have NEVER seen this happen for one positive UA.
Unit commanders frequently try to do this and get upset when they are told they can’t. This will probably be one of the cases where the command wants to separate the Soldier under a Chapter 14-12c, Serious Misconduct, with a General Discharge, but they just don’t have enough time to complete the action before the Soldier’s ETS. The Soldier will ETS with a Honorable discharge with all benefits. The only thing the command can really do is max the Soldier out on a Field Grade Article 15.