Is he still extremely lean? Sad to see people living like this. More to life than being ripped.I have met lots of severely underweight ectomorphs, with terrible metabolisms and constant mood swings, who try to reinvent their dysfunction as a virtue and accomplishment. It's the other end of the "beautiful at any size" spectrum.
A very close friend of mine is 5'10" and has never weighed more than 140 lbs. He developed psychological issues with food at a young age, and as we got older, he started suppressing his appetite with black coffee and cigarettes in order to avoid eating, never ate breakfast, etc. He couldn't change his habits, partly because he didn't want to give up on his lean, "shredded" look, so in his early 20s he burned out spectacularly. I talk to him on the phone every once in a while, but he's still stuck in our hometown, with nothing really going on in his life, and he strikes me as the perfect exemplar of what happens to even a competent, intelligent person if they have to deal with a chronic unavailability of energy.