They will probably promote him under some schedule and the assumption that he would have been promoted at the same pace had he not disappeared and been taken captive. Then they will try him in military court and find him guilty of being a jack ass, bust him down to corporal or private, give him five years at Leavenworth for going off wandering. They'll suspend the sentence for time served as a Taliban captive, give him an other than honorable discharge. He'll lose whatever pension he had but will receive back pay, and everyone will go back to business. Then he'll wander off into Canada.