Not to be nosey, but at age seventeen how much hunting experience does he have?
Most PHs I know (all in South Africa) have a solid backup profession for the off season. Your lad should be encouraged to educate/train himself in an alternate vocation. Many PHs are also landowners who manage agricultural farms. My first (and still favorite) PH did security work and/or carpentry when not guiding. One ran his father's sheep operation. Game farm management is a degree course at universities. It's much more complicated business than one might think. A degree in that field would be very useful for anyone wanting to get into PH biz. Some of the safari farms are being bought up by foreigners who quite literally know nothing about farm management. They just like to shoot stuff. So they need someone who can manage the farm as well as guide clients. Or veterinarian degree but of course that is quite a rigorous and expensive program. South Africa seems to be flooded with park guiding schools right now. Personally, as a retired US park ranger, I would not encourage your son to go with those shake-and-bake schools (we have them over here too). Get a real degree in biology or agriculture. I have a PhD in history with a second BA in biology + other science. And certified to teach it all. So I could work park interpretation at any unit, historical or natural (often both). Besides teaching and park ranger, I was also formerly a policeman, firefighter, emergency medical tech, animal packer (horses & mules), crane operator, finish carpenter, cartographer, and truck driver. I'm sure I've forgot a few of my jobs. Point being, I was never out of work. Always have a backup plan/skill. From what I could see, a backup plan would be especially important in South Africa.
Edit: I'm sure PHASA would be the best first step in investigating pursuit of PH career.