Andy paused when he heard the question, he had never expected he would need to explain something like that. "Well," he began with a shrug, "in a body with a healthy mind that is an automatic process. Sleep is a kind of unconscious state that just happens when we relax when we are tired and we wake up from it automatically, when the body and brain had enough rest, or an external stimulus wakes us up. If you will lie in the bed it should just happen by itself, but if you worry a lot about your current situation or start plotting or whatever it may take a while before you fall asleep. That is also normal, with an active mind it's harder to fall asleep, but eventually the fatigue will take over." 

He gestured with his thumb over his shoulder. "If you need me, I'll be sleeping in the room on the other side. But I'll probably watch some TV first."

Had he covered the basics now? He thought he had. In the morning he could see about getting the man a toothbrush and explain a bit more about personal hygiene, if that was also something he wasn't aware of.