Ah, you know how fickle kids are. One day they hate something, the next day they can't get enough of it. When I was an urchin, I loathed Swanson frozen TV dinner chicken, and then it was all I would ever eat. Same with David: first he sees Barnabas as some monster living in a casket trying to murder him, and then he's his bestest, bestest friend in the world. TV dinner chicken or vampires, to kids it's all the same.
Gerard