The Grand Marshal thing is a nice gesture, and should help the family to know that they have support and that Bowe is not forgotten.
Getting promoted to Sergeant seems a bit odd to me. Promotions from E1 - E4, Private to Specialist (or corporal, in some cases) really aren't promotions. They're "advancements," and they're pretty much automatic. You get advanced unless there is some reason not to.
Promotion to Sergeant is another matter. It's competitive, and you have to meet certain requirements. Good reviews, pass the PT tests, make weight, etc. Bowe just cannot meet those requirements while in captivity. So, someone somewhere decided to waive the requirement and promote Bowe. Which is nice. It will certainly help with his pay, which must be accumulating somewhere.
However, if, as some report, he violated the rules and wandered off base and put himself in a position to be captured, it seems a bit of a stretch to promote him. But it's not clear.
Accounts of his capture differ. The version offered by Bergdahl, in the video, is that he was captured when he fell behind on a patrol. CNN, in its report, cites both Taliban and U.S. military sources, the former alleging he was ambushed after becoming drunk off base, and the latter denying that claim stating: "The Taliban are known for lying and what they are claiming (is) not true."If he fell behind on patrol and was captured, the Army should know that for a rock-hard fact. Perhaps the promotion indicates that the Army is not viewing the circumstances of his capture as reflecting negatively on him. It doesn't matter now, of course. I just hope he gets out safely.
Little known fact: the Army has appointed a Major - he's in my unit and he's a high-speed guy - to be the sole point of contact with Bowe's family. Anything and everything that causes contact between the Army and the Bergdahl goes through this Major. And, he's got the appointment until the situation resolves. It's a way to try to make it easier on the family.