Sounds like typical teen behavior to me.
I would make sure he has food he likes, since he's just eating Kashi. Not eating much protein can actually worsen depression, if that is a concern. So I would try to work with him on that. It might be a common area you can connect on.
A wise woman once told me when kids get to be teenagers, they go away for a while. Some just for a short time, others for longer and in the meantime there is a stranger in their place. But eventually your kid will come back.
I don't think you should. What I would do is help him make plans with his friend and offer to give rides, etc.