I Think My Dad is Dracula

I think my dad is Dracula.
I know that sounds insane,
but listen for a moment and
allow me to explain.
We don't live in a castle,
and we never sleep in caves.
But, still, there's something weird1
about the way my dad behaves.
I never see him go out
in the daytime when it's light.
He sleeps all day till evening,
then he leaves the house at night.
He comes home in the morning
saying, "Man, I'm really dead!"
He kisses us goodnight, and then
by sunrise he's in bed.
My mom heard my suspicion
and she said, "You're not too swift.
Your father's not a vampire2.
He just works the graveyard3 shift."