He wasn't court-martialed, and the Army doesn't have jurisdiction over him, but since he pleaded guilty to something he did while he was active duty, the Secretary of the Army can convene a grade determination board to consider what grade he last served honorably. I would bet he gets busted back to Major, maybe even Captain. The difference in retired pay alone would be huge.

As someone who has met him, he's a despicable person and it couldn't happen to a more deserving person.