I went to a community college that offered a certificate in recording technology which you could complete in about 3 semesters. When I was about to finish I started asking around at the bigger recording studios in the area, and found that they also offer classes. Again, about 3 semesters, much more expensive, but they told me they mostly hired out of their own training program. Finally there are universities that offer 4 year degrees (If I remember correctly, Tennessee is supposed to have a good program)
If he wants to have any chance of working for someone else (major recording studio, TV network, film studio) he should do the university route. If he ends up working for himself like most people in the field, it can be a little hand to mouth. Especially at first. If he does end up working for himself the training he has doesn't matter so much as what kind of finished product he turns out. It's pretty competitive and you have to find all of your own clients. Modern technology has made it much easier and cheaper to set up a studio these days (Say $50,000 for a decent studio versus the half million a comparable studio might have cost in 1985) but it also means a lot more people are getting into the racket.
Another career he might end up in would be live sound. There are companies that might hire him to do that, but they may require him to have his own equipment (in which case we're talking at least $8-10,000 worth of gear) and he'll be working nights and getting in around 4AM.
To sum up, he'll be able to make a living doing this (if he's good), but it is work, and it's very unlikely he'll get rich (or even upper middle class) doing it, so he's going to have to be sure it's what he loves or he's not going to make it.
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