mmk.
I don't know that there is a real guide that will go through all this, but I'll give a quick starter.
Well, shuffling is definitely where he should start. It is super important as falcon. If he understands how to do it, it is really just about drilling the muscle memory until he has it down. It's not much fun, but it pays huge dividends. If he's having trouble with that have him check out Wak's how to play vids, they are very good. Then maybe learning how to dash dance correctly, you could show him vids of just about any top falcon and they'll be doing it. I've always admired Hax's dash dancing, but that could just be personal preference. Wavedashing can also be good, especially out of shield.
Idk, I'm not the best one to say these things, as I'm a pretty bad falcon, but definitely shuffling first.