A caution...
Texcalif--I know that several others have made interesting suggestions for your son re: a career involving firearms and shooting. I am going to suggest something else: Make a career of doing whatever he's good at, that does NOT involve firearms and shooting. Then when he wants a relaxing rest from his job, he can go shooting, or hunting, or reloading, or whatever, that he loves.
I say this as an experienced bicycle salesman, who quit selling bikes because you have to be in the store when people have time to shop, and that precluded ever going on one of those nice Sat. or Sun. organized rides with my friends. I still love bicycling, and now I can do it when I please.
Same is true in the hunting/shooting area. I hunt, and shoot, and love both. I studied wildlife mgt. in college, and considered a career as a warden--Until I realized that during hunting season, wardens NEVER get a day off, they are on duty 24/7. And during fishing season, guess what wardens are doing on the good fishing days--Checking licenses and bag limits, not fishing themselves! The hours all year are awful--poachers don't wait until you're rested up. And, every now and then, you get to go to court and be verbally abused by a defense attorney. Now, if you love enforcing the rules, and being out there managing the hunters and fishers, and educating the young'uns, wardening is fine. Just don't get a job as a warden if you expect to get a lot of hunting/fishing time in yourself!
What I'm saying is, if you love a particular activity, keep that for your own time, and make money at something you can put aside for your loved activity. Unless, of course, your son is a good enough shot that he could actively compete at the national/international level. That's a career, too, but those who are that good, and have the determination to do the necessary and constant practice, are really rare specimens, and can make quite a good living at it. But, it IS a very full-time job. The likes of David Tubb, or Doug Koenig, don't get to go duck hunting very often.
Anyhow, good luck to your 15yo, and I hope he finds a satisfying career.