unfortunately, I would have to agree ^^ he's too young.

at his age, his endocrine system is still developing, and by introducing additional hormones into his system, it will change their development, and not for the better. Typically, the endocrine system fully matures in the mid twenties.

Here is the link from wiki:
http://en.wikipedia.org/wiki/Endocrine_system

there isn't a single knowledgeable person here that would recommend what your "friend" is contemplating. The reality is, it has only been a few years since puberty, and his hormones are all over the place right now anyways.

Introducing anavar at such an early age runs a very real risk of shutting down the HPTA system. If this happens, serious problems could result, such as abnormally low testosterone production, ED, low libido, etc.
here is the wiki link for that:
http://en.wikipedia.org/wiki/HPTA

this child will ultimately do what he wants to do. Unfortunately, there is little you or I can do to stop him.