I typed "where does he sleep", and it was wrong. Why? There wasn't difference between the present tenses before.
The translation says 'hvor' is both 'how' and 'where'. How do you know which one is referred to?
If you wanted to ask "how does he sleep?" you would say "hvordan sover han?"
Hvor is 'how' in the context of saying something like, "How strange!" ("Hvor mærkeligt!"), and never, I believe, as a question (though I'm sure someone here will disabuse me of that notion :).
Beyond standard "where" uses, you use "hvor" as "how" in questions that deal with amounts. There might be more times to use "hvor", but it is used with amounts.
"Hvor mange?" - How many?
"Hvor længe?" - How long?