I knew kids like this in art college. A lot of young, fledgling artists go through this <annoying> phase where using any kind of reference material is viewed as some mortal sin. Usually it's because they're under the naive (and false) impression that their favorite professional artists probably don't use references and draw everything from memory. But I could practically guarantee you that as your friend gets older and becomes more experienced, he'll come to realize how important references are.
Unless they're an absolute
savant like
Kim Jung Gi, only a foolish artist doesn't use reference material, at least if they're genuinely trying to accurately capture a person/figure's likeness. I illustrate portraits of kids as my day job (see my post above) and I couldn't imagine trying to capture their likeness with any amount of accuracy without a reference photo to work from. I don't use grids, but that's only because my illustrations are stylized and I'm not looking to achieve 100% realism.
Now, straight-up tracing a photograph is certainly a more questionable practice. But even then, it depends on what you mean when you say "trace".