I was worried about ghosts when I was a kid. We lived in a house that my mother's family had built. My mother said, well the only people who lived here who have died are your grandmother and grandfather. They loved you very much. If they are here as ghosts then the only reason I can imagine they would be in your room is to take care of you and protect you. It worked, and, in retrospect, I found that much more comforting than trying to talk me out of my fears.