It's not a direct answer to your question but within any group of commissioning officers, the needs of the service factor into who gets to do what in their service selections. The coast guard, navy, marine, and some foreign pilots from ally nations all train together in the same pipelines and there is no guarantee even if you service-select as an aviator in a marine-air contract or as a student naval aviator, that you'll fly fixed v rotary wing craft. General gouge is that coast guard and marine pilots more often than not fly rotary, but for your specific class, who knows? I've gotten to know now a few young people who were pegged on becoming a pilot but after they self-selected pilot as their top choice, are now serving on a ship, or sub, or sitting in the flight officer NFO (Goose) seat instead. Recommend he/ you research backup options in each service branch - if I can't be a pilot which service has the best alt. roles for my interest. Again, no guarantees but at least you can pursue the best fit.
You mention he has no flight experience - if you can afford it, pay for a flight lesson this month before decisions are due that gets him up at the yoke in the air in a small craft - see if he likes it. Met a number of people who went to Purdue/ Embry Riddle/ one to Ohio State to become a pilot who amazingly had never flown in a plane - even once, and ended up learning the reality wasn't matching their expectations. Not everyone likes it, and that is ok... One orientation flight for my son as a young teen and he was hooked for life... Try it before making such a commitment is my recommendation.
Good luck and thanks for his willingness to serve.