I did my CP last year at Kilimanjaro Safaris and it was a wonderful experience, and I am currently in the running for a PI with Animal Programs. During the CP, students won't have any direct contact with animals, but it is an excellent opportunity to network and get to know leaders that may be able to help your son get where he wants to be. Not all Animal Programs PIs require you to have done a CP first, but a few do, so he'll definitely want to look into that.
It's great that your son already knows what he wants to do! One thing he can do to help boost his chances of getting an Animal Programs internship is to start volunteering (at a shelter, zoo, vet clinic, etc.) and when he gets to college, take classes relating to what he wants to do, as well as continuing to volunteer or work with animals as much as possible. Hope this helps!