“.......a less than honorable discharge and maybe jail time.”...
That will be the ONLY correct decision.
He deserted and consequently many other soldiers died trying to get him back. NO EXCUSES, the bastard deserted and deserves the MAXIMUM punishment, not an increase in rank and back pay.
Not sure whom you were quoting there, but that certainly isn’t what I’d like to see him get. I’d say that will be the end result, however.