I believe the one on the left is the original

yes. that^

I think that's really nice, lines, dynamic, abstract things, all is nice. I like more black/white/gray/red original. Your friend definitely should try to find some work as a pin-up artist. Comics and stuff.

he definitely has talent. he's still too young for work. he's only 16. it just means he has more time to improve.

That's the most bull-crap thing I've read in a while.

You're never too young to work if you want to, look at that 10/12 year old kid working for Microsoft. Bad example, I know. What I'm trying to say is that 16 isn't too young to start to work with comics and stuff like 8ojan mentioned.

yea. i'm sorry if you think that's crap. i'm in singapore. How we get our jobs are through the black and white certificate. No cert, no job. It does suck for some jobs. It's even harder for artists in singapore since we're not all too cultured for arts.

Idk how things work in Singapore, but if he can post his stuff on internet he can find some freelance work. And if PayPal works in Singapore he can even get some cash. Tell him to try, there's nothing to lose except some spare time.
Like, in France, manga is now stuff that ppl wants, and they always look for manga artists. Looking his work I say he can give it a try.

9/10. nice work m8.

I'm having trouble believing that's hand-drawn, specially because of the uniformity of the shading and the fact that it has a transparent background which shows a layer with clean borders. Could you show the directly scanned picture please?
I'd also like to stress out that if anyone went to a non-specialised art school, they wouldn't end up drawing standard, un-nosed, giant eye figures so that went without saying.
If he really did hand-draw this, though, then I guess he could work on making the hand fit more with the arm. In shape and maybe in colour (I'd need to see it as it was drawn to judge the latter). If he's not narrow-minded about the whole manga thing he could try to draw people and attempt to make them recognisable, that's really hard to do but it's rewarding. To train, I suggest drawing from pictures to get a feel of people's anatomy. He should avoid using the standard proportions which are easy to find on the internet because it makes the people unrecognisable and only drawable from the front.

it was drawn as seen below.


those tips would help alot. i'll definitely show them to my friend. Thanks!