I really don't think we're talking about some driven child star with natural ability or a family pushing him into music. Just a regular 15 year old who still has a ways to go in his own musical journey.Guys...this pup was born in June 1991,so he's closer to 22 actualy,not 15 according to his profile.
How many hits did Michael Jackson have before he was 20.Stevie Wonder was signed to Mowtown by 11,and had a hit at 13.Steve Winwood was not much older when he had a hit with Gimme Some Lovin" at 16 or 17.
I'm an advocate of playing with as many people as you can, whenever you can, so I'm not discouraging anything. Just sayin. Don't ditch your best buds because you guys aren't being a power-house whipping through recording sessions at 15. I still think you have a few years before you really need to try and be "productive". The most pushy I'd be is maybe trying to setup some gigs... Which could lead to writing or learning, which could eventually lead to tightening up and working on this stuff more professionally.