Ghosts.. Friendly or not ?

In the Graveyard Book, the setting is obviously a graveyard, which graveyards are known to have ghosts haunting them. In this book the baby , Nobody, finds his way to the graveyard and 2 ghosts appear and decide to take him in as their own child. When i read this i found it absolutely crazy that ghosts could raise a child. Most people today portray ghosts as being scary figures, but in this book the ghosts become this child's family. They are very loving to the baby which just doesn't seem right to us. I myself always pictured ghosts as being scary, and mean, but after reading this book i am pretty sure that my beliefs will change. I think this is one of very few books or movies that have ghosts portrayed as friendly creatures. I can think of one other movie where a ghost is friendly and that would be Casper. Can you think of anymore? Did you find it strange for the ghosts to be friendly in this book?