Average student coming out of culinary school who works in a restaurant will make between $9-12 an hour in a local, single owner style restaurant. If you're doing corporate you can tack on a buck or two an hour to that. Honestly my biggest advice is for your a culinary student to find the job they want to be in after culinary school, but start it way before they graduate. That way they are using their degree to gun for a management/lead cook role, instead of using it as a line on the resume. Honestly, It will all depend on their personal drive and connections they've made while they are coming up.
Honestly, it depends on what they want to do when they graduate. I have a student who was making 65k right out of culinary school with a 5 year contract with her employer that would scale up to 100k if she met all incentives. She didn't cook, she applied her culinary knowledge in demos/sales pitches and sold her company equipment all over the place. She spent a week in Beijing for example to land a fairly huge account. Now I'm not saying that is the norm, but she thought outside the box and looked for a job that she would be excellent at and got it. If you're boyfriend has the idea that he must work in a locally owned restaurant after his degree, he won't see a return on his investment for quite a while.
Of the dozen people or so I was close to in my Sullivan Labs (2005 graduate) here's where they have ended up:
Girl 1 - Pastry Degree - runs an AIDs clinic
Girl 2 - Pastry Degree - Cooked for a year and went back to school in an unrelated field
Girl 3 - Culinary Degree - Returned to her former Lab Tech job (not sure if she ever actually even went into the Culinary Field)
Best Buddy 1 - Runs a construction company now (this one is deceptive, it was the family business and I think was a forgone conclusion, no matter what degree he got)
Buddy 2 - Culinary Degree - Now a marine, but did a ton of line work in town until then (and has said he wants to do it again once his term ends)
Buddy 3 - Culinary Degree - Underpaid Sous Chef
Buddy 4 - Culinary Degree - Lost track of, but last we heard he was still cooking in Portland Oregon
Buddy 5- Culinary Degree (unfinished) - Special Forces (why he dropped out)
Associate 1 - Culinary Degree - Exec or Chef de Cuisine at fine dining restaurant in town
Myself - Culinary Degree - Sous Chef
Looking back over that list, the overriding theme is that over half of the people I have kept in touch with in culinary school will not use their degree. Of the ones who are still cooking, all of us did it BEFORE going to Sullivan (1 exception to that). The rest tried their hands at it, and decided the life was not for them. Tell your boyfriend to go work in the industry for 6 months, and if he loves it, Sullivan will be worth the investment. Not to insure a huge salary but to insure that he has a decent skill set to push him in a career he greatly enjoys. If he is wishywashy, cook for another 6 months and reevaluate, if he is unhappy, save the money and do something else.
Edit: Reread your 2nd post in the thread, and see that he has done cooking professionally, but going to leave the original paragraph for anyone else reading.