It seems like something is definitely going on. But if he enjoys hanging out with his friends and all of that then apparently there isn't anything social about it (such as social anxiety or phobia) which is a lot of times the cause.

It could be depression, but have you tried talking to him about it? That would be the best place to start. If he is depressed, try to find out WHY he is depressed.

The next thing to do if you find out something is bothering him is to try to get him to some sort of therapy. Normally the schools have trained counselors and their help is generally free so that is a good place to start.

Next, if you find out nothing is wrong and he just doesn't like getting up in the mornings, is to find a way to enforce him getting up in the mornings. Is there any way you can do that? Or do you and your husband both work during that time? If not, there does come a time when you have to enforce that he goes to school, because if he misses too much it will get YOU in trouble. Unless wherever you live students are allowed to drop out at 15 but here they are not.

After a few days of HAVING to wake up in the early hours, he will start to get used to it and believe me, he won't want to stay up late. You won't even have to give him a bed time. I would let him have the TV and Computer for a night without telling him that he is waking up in the morning no matter what. It may be tough love, but as a parent you have to make sure he goes to school while it's the law.

Last words, don't be too upset over it. This is normal behavior from many children. My younger brother was the same way, but once his parents started forcing him to wake up and go to school and they even took away his bed time he knew that he had to go to sleep early and he was too tired to stay up anyways. So, don't fret too much. It might not be that there is anything wrong with him at all, since it's normal, and perhaps he just needs someone to give him that push.

Hope I helped some.