Walter Reed may not be in the fanciest of neighborhoods, but I don't think that orders to report to his brigade commander's office equates to being sent on a combat mission.
Show me the order he disobeyed which is not part of his orders to deploy to Afghanistan.
And as long as there is any instance where he’s charged with disobeying an order connected to the deployment orders then he has a right to defend himself against that charge. Anything he disobeyed that was associated with the deployment order is documentably dependent on a valid POTUS in order to be “lawful”.
A darn good case has been made for the lawfulness of ALL orders being dependent on a valid, Constitutional POTUS, but the “use of force” orders are certifiably dependent, according to Lind’s own statement that Congress has some authority over military matters - because Congress expressly gave that authority ONLY to “the President”.