Why you didnt try async work like how Automattic does? The people could answer his questions in the morning, he could answer other people's questions at his morning. From Slack to Jira there is a plethora of collaboration tools which enable this today.

The true power of remote work - aside from removing the waste of commute time - is that it can be tailored to anyone's life, anywhere.

Let the person sleep whenever, however he wants. Use async tools to keep work going around the clock.