He enlisted in the Army and got a security clearance, which is the credential that's really crucial for CIA/NSA/contractor jobs. The Army is willing to accept a GED, which you can get in an afternoon.
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?
Yes, that's what I mean by "willing to accept". If a person's ASVAB scores are high and they're not a total mess, they can get a waiver for many things. It varies by service, of course; I'm not surprised that the Marines and Air Force don't waiver GEDs.