Hasn't he heard of time travel? She has clearly slipped through a gap in the fabric of time, and lost her conscious memory as she did so. But not her unconscious memories, maybe. Of course, I've been wrong before with your stories, so we shall see.
I know many of your stories feature ghosts, but this time I think she's a time traveller.
Ha ha, you're right about one thing - she is not a ghost. I think people who are practical minded are really closed to what they think are impossibilities - Scott is slowly having his eyes opened to a mystery of life he isn't even aware of...yet.