So, I'm going to assume we're talking about a real condition here. This is because that's the first thing you can do: believe your friend when he tells you he

So, I'm going to assume we're talking about a real condition here. This is because that's the first thing you can do: believe your friend when he tells you he's sick. He probably has doctors, family members, and peers constantly not believing him. Just having someone not question it can help a lot. Second, you can't force him to change his life around. If someone honestly believes something beyond their capacity (physical or mental), you're not going to be able to coax, reason, berate, intimidate, or threaten them into doing it. What you can do is inspire them. Give them a reason to wake up just a little sooner, like a shared activity that you both enjoy. "Let's have a match of <X game> before I go to bed tomorrow", or maybe "I'm making X for dinner, I'll make extra for you if you're up". Try something like that. Small steps are best to start with. Trying to force someone in a big step will probably cause a panic reaction. A confrontational approach will probably do the same thing. A panic reaction is not what you want.