I got made fun of as a child by a parent for doing art and just... never did any ever afterwards. I primarily hang around artists tho and would like to relate to them more, but none of them do creative writing. I've read numerous grammar books, so that won't be a problem, but none really go in to how to construct a sentence, paragraph, page, chapter, plot, etc. I'll happily take any advice on the subject, really anything you can think for someone with actually zero experience.
Good advice I've gotten so far is to just write basically whatever. Also, people who are visual artists and creative writers, which was "easier" for you to become fluent?
College is probably best for getting feedback on your work. But he should probably do the preliminary legwork himself through some self study for a few months. Just to get the bare basics.