Exactly who can be a qualifying relative and who cant???

Say, for example, that you are unmarried but have a friend who lives with you full-time / all year. Its just the two of you (and maybe a quadruped or two). The apartment (or house) is in your name only and you pay all of the rent (or mort-gage) and for absolutely everything else because your friend is a writer who does nothing by way of work other than on a supposed novel which of course brings in absolutely zero income because it never seems to get finished, much less published

Since youre the sole breadwinner and its your apartment (or house), can you file as Head of household instead of as Single? Explain in 2-3 sentences.