My heart goes out to you. My son got sick at 16, though in retrospect we realized he'd been going downhill for a year before that. He turns 21 next month. No drivers licence, no parties, no school, no friends dropping by. His life in on the internet and with his parents and brother and sisters.
The hope is that he will completely recover. He is much better than he was 4 yrs ago -- mind you the baseline then was very low. He couldn't be out of bed, could hardly hold his head up, I practically fed him, and he couldn't follow conversations. Slept most of the time, but all the "wrong" hours, up at night, slept during the day. But he is able now to be up some of the "right" hours. He has applied for a parttime-parttime-parttime job at a local grocery store. We all know he may not be able to do it but he might because he's been regaining ground that well. Just very slowly.
I have some articles about my son on my website www.ncubator.ca if you are interested in checking them out, he was 18 like you when I started writing them. They end abruptly a year or so ago but that's because I started working as a freelancer then and haven't been able to keep up with my own writing. Not complaining, I love being able to work.:)
Hang on to hope, even when it seems like there's no reason for it. Especially then. Require life to come to you. Meantime ... get some rest. :)