Unless something has drastically changed in the last few years, flight training generally lasts for 2-3 years. 1 year of 'undergraduate' flight training, plus more specialized training on specific aircraft.
I have no idea what your friend is doing that will take a decade(?!) to complete.
source: Air Force brat, father was a flight surgeon.
20-year olds flew the bombers that won World War II, at the very least.
I'm skeptical that bomber pilot training really takes 10 years--that seems a tremendous waste in the military. 10 years is half of your active duty career if you stay in the military until retirement.
Well, the other half of WWII ;) Naturally you'd pick a very experienced pilot to drop The Atomic Fucking Bomb, but the average age of bomber pilots over Europe was famously in the early 20's.
His comment meant that 20-somethings shouldn't be disallowed from flying nuclear bombers due to age alone. In other words, if your friend somehow finished training in 5 years but wasn't allowed due to being less than 30 years of age.