Your son definitely sounds like he is depressed.
When I was around 16-17, I was really depressed as well.. I was in my senior year of high school, and even though I had friends, I didn't like them. My family pretty much knew that I was depressed, but they never did anything to help. In fact, they made it worse.
So I felt alone..
It's great that you're trying to be there for him and that you try to cook his favorite foods. You're a great mother for being so supportive and for not nagging him, as he is obviously going through a difficult time.
Something that would have helped me when I was depressed would have been to have someone to talk to.. make yourself available to your son.. and don't ever judge him.. let him have his own thoughts/feelings/opinions.
Don't let your husband disconnect his internet!!!
When i was depressed, the thing that helped me the most was the internet.
I had some internet friends as well, some that I could really talk to and that wouldn't judge me or make me feel bad about myself. If your son has that, even if not from a friend he knows personally, don't take that away from him.
My parents would limit my time on the internet and wouldn't leave me alone. They made me feel horrible about sleeping a lot and about not wanting to go out or do anything. They called me lazy, fat, etc.. Make sure that your husband doesn't call him any names or makes him feel bad about himself.
It's good that he's seeing a counselor at school.. if that's not helping him, maybe you can find someone outside of school that he can see.

It's very difficult, but I think you are doing the right thing. Your son is very lucky to have such a wonderful, supportive mother.
Good luck