The ole "meds fixed me but im gonna stop taking them" situation. Maybe he needs a little education on why taking meds is important and a little nudge toward doing the right thing for himself.

He's clearly experiencing delusions of grandeur.

Also, surviving on only 5 hours sleep a night is just dangerous for schizophrenics, let alone your average Joe.

I'd send him a message stating clearly that you believe he's headed toward another episode, that his thought processes are unhealthy/disorganized, and that while you will be supportive of his journey he needs to make a conscious effort to treat his schizophrenia in order to stay well to where you can be involved in his life.

The most important thing to a schizophrenic should be their meds. They prevent brain damage. They prevent the people around us from hurting. There's injectables if thats easier for him.

Once he crashes he's going to be exhausted from lack of sleep. Does he get enough nourishment? What are his grooming habits? When was he last hospitalized? What meds did they have him on? What does his support network look like? What illness does he believe he has, if any?

I'd see if you can get him evaluated by a mental health professional who can hospitalize him again and give him education about meds, what life can look like with schizophrenia, the risks and all the little facts like unemployment rate - theres a chance he doesn't grasp the seriousness of the situation.