The desertion charge is a no brainer. His entire unit and every other bit of evidence says he deserted. The ‘misbehavior before the enemy’ charge will be harder to prove, but it suggests they have evidence of his time in captivity. I don’t think they’ve Article 32’d this yet, have they?
His lawyer should plea bargain for your suggested 3-5 year stint and consider it a gift from the American people. Obama will heave a sigh of relief. If this goes to trial and consorting with the enemy is proven, then the Qatar 5 will appear to be totally criminal (which it is).
Nope, you get that for deserting stateside. He deserted in a time of war in a combat zone and he went over to the other side. That is firing squad level.