Poll: Guys shall i ask him..............................?

I have a very good friend of mine. He has been always supportive towards me. He always helps me in tough times. But there is something that I don't understand about him. This guy always wears black color clothes. You won't believe me i have never seen him wearing any other color clothes, since one year. Even though we guys love to wear black, but we too wear other color clothes. Whenever i call him in the morning, i always find him sleeping, as informed by his parents. This guy told me that he does a night duty. I don't know which night duty he does. So my question is ' Shall i ask him that is he a vampire?'