For one, he didn't enlist, he is a commissioned officer. And as he is only a lieutenant, he has less than four years of active duty, meaning he joined after 9/11/2001. As such, he should have had a better idea of what he was getting into...
Failure to Go falls under Article 86 (Absence without leave) of the US Uniformed Code of Military Justice. I am sure he will feel the full brunt of that code, if his I Corps Army buddies don't kick his ass first!
An Army of One!
Cheers! M2