I am 22 and began seriously around that age. Shooting film with almost no money made me very selective, though now I see that it prevented me from doing extensive work about certain subjects. If I were as I was 15, a stash of film and some help in developing would do lots.
A friend got recently into photography and it's been a nice excercise to me about evaluating purpose and photography. He initially was a bit lured by an acquitance who said he could get lots of girls by shooting studio (hah!) but when I took him around a couple of locations he found that the real interest is to enjoy one's own photography and not try to chase other things or please others.
In addition to shooting more, tell him to make photos of his friends, just doing their day to day activities. I was looking at some 12 year old photos from when i was at university recently, the memories it brought back are one of the things I love about photography! Many of the people in the shots I probably haven't seen for over a decade, but i can still recall so much about them from those photos.
This is very, if not one of the most important things. I graduated college, shot a lot (phone specially) but little film -- Still, heaps of photographs that will be nostalgia material soon.
About instagram. I have one but only use it to comment fellow photogs. The problem there is that you mix up the (non defined yet) purpose of his photography with laypeople that post selfies and such. -- May throw off the perception of his own photography. Still, IG has lots of great photographers; but I'd be cautious. I found myself doing what Calzone said about being rather kept to oneself in photography.
And gear, it's better to start off simple. My friend got an LX100 with its 24-75 lens which is just perfect for everything. Heck, even a single prime (35, 50) is great to set things down and not get confused playing with focals. I know another guy who has a big DSLR, the 24-70, 70-200 f2.8's and a couple of 50mm, recently bought an f1.4. For? Just getting confused and use a helluva expensive and heavy lens rather wrong.
I would be careful not to overwhelm him and make it not fun. Just go out and photograph with him.
That's it. If he still doesn't have the hang of settings, it takes a while of practice.
Excuse me if there is a bit of a blunt tone, just came back from a few too miles of cycling. Photography is a nice hobby that gets along others, like travel.
