Article 88: Disrespect Towards Officials
Article 94: Mutiny or Sedition
I think the sticking point on Mutiny would be that he didn't do this in concert with other military members.
He is definitely going down for Art 88 Contempt, 87 Missing Movement, 133 Conduct Unbecoming. I don't know if you can charge him with Failure to Obey a General Order and Missing Movement, although his missing movement was definitely planned.
If the Army really wanted to go after him they would get the Feds to seize his computer and see if there is any hard evidence of this being planned from the time he decided to enter the military. If he entered via OCS and signed after the OIF commenced then we know this stunt was the whole reason for joining. Then you get him for Art. 83 Fraudulent Enlistment, 81 Conspiracy, 107 False Official Statement, and throw in 134 just for fun.