Good for him! My dad joined the Air Force right after high school rather than get drafted. He wasn’t a stand out student at the time, but he was motivated to not go into the army.
He used the GI money to go to University when he got out, and chalks up the work ethic he received in the Air Force, as well as the additional maturity he had at that point (as compared to the 18 year old freshmen) to go on to graduate in 3 years. Ended up the CEO of a large international region of global company.