Well, I was never very fast or natural at learning. I just kept plugging along, and now, though I'm not as good as 15 years of playing would have you think, I'm good enough.

For some people, it just clicks. But I don't believe in giving up just because it doesn't click. I've heard many times before that if you're an early teen boy learning to play, you will learn 5-10 times faster than anybody else. No explanation for that, but there's tons of empirical evidence for it. Perhaps that has to do with how easy or hard it is for someone.

I'd certainly encourage your friend to just keep hacking away. Might not be a quick journey, but it's not like quitting really gets him anything either.