This is actually counter to what I've been told by several high ranking friends I know in the military. I have a family member who is a full bird Marine Colonel and he said they won't take GED candidates anymore. I also have a good friend who's a Senior Master Sergeant in the Air Force and said the same thing.
Here's an article from 2009:
http://www.nodropouts.org/blog/bad-economy-bad-news-dropouts...
"Army recruiters now tell potential recruits that their chances of getting into the service are not good if they don't have a high school diploma. And even a GED won't cut it in most cases."
I did notice the "in most cases" language, so maybe he got in on a pass from someone?