Good, that is the information I was looking for. Thank you.
I Took the beginner 3M course to become car wrap certified. It was a few hours of explaining all the products... whats good for what, and then a few hours of everyone practicing wrapping a complete car. I wrapped about 50-100 boxes before the course... so I knew 99% of what they told me. I think it's a decent course for a beginner, but honestly... Hands on experience is better. Take the money that the course would cost, and cut up a couple blank panels, tell him to practice. Wrapping a mirror is different than wrapping a straight door, as is putting window perf on the back / sides.
If he REALLY wants to learn, thats the best way. I didn't need someone by me telling me I'm doing it wrong... If I see a wrinkle, or the text becomes warped, I know I did it wrong, and I'll fix it / figure out a diff way to do it. Youtube is great... Theres tons of videos. The good thing about wrapping is everyone has their own style - There isn't just 1 "Correct" way.... Sure, theres certain things you need to know like don't vinyl over rubber, don't cut into the car with your blade... etc. But most of what he needs to know will be in every single wrapping video, the technique is something he has to get down for himself.
When I was first learning I loved it. The day after my first electrical box (Most are really flat and easy...) I grabbed a hard hat and tried to wrap that. As much of a failure as that was, it was fun... and it taught me a lot about how to do round objects. Since then... I've wrapped 100's of random objects, just to learn how to do the curves "better". I can confidently wrap most things I try... The speed is an issue on some stuff, I'm probably 1/2 as fast as my co-worker who's been doing this for 20 years... But it's still fun. I've been doing it for a year... not 8 hours a day, or even 1 hour a day... but I've wrapped maybe a couple full cars, 2 busses, 50-100 electrical boxes... and I still consider myself a beginner. Everytime I go out, I learn something new.... Thats what your nephew needs, the practice. He can learn the basics from youtube, and the rest he figures out by watching others either in a shop, or on youtube, and adapts it to his own way.
TLDR; The course can help a bit, but i found it more geared towards teaching you what materials and stuff. The best way, as others have mentioned...send him a box of scraps, they dont need to be big... Just enough to practice on mirrors, helmets, a small side panel/fender... Anything. Have him come visit for the weekend, teach him the basics.... and send him home with a box of scraps, thats all he needs. Wrapping also isn't for everyone, he may find he hates it after he tries it.