Songs for ghost/human relationships?

I've thought of two songs that might be what you're looking for

The first one is taken from the film "ghost" and is called Unchained Melody. I found an instrumental version so hope you like

Here's a youtube link so you can have a listen to it

http://www.youtube.com/watch?v=hVEMhNrZv9g

Another idea of mine is to use this one from the girl band B*witched and it's called "are you a ghost?"

I absolutly love this song and the lyrics are amazing

I found a youtube link which you can have a listen to and see what you think?

http://www.youtube.com/watch?v=DOnpAV0u4rY

It's very calming and easy to imagine the scenario

Hope I helped in some way and really wish you the best of luck

Thoughts of a Dying Atheist - Muse

One line goes "i know your in this room, i'm sure I heard you sigh, floating on between where our worlds collide"

it's a beautiful song about someone who faces death and wonders whether they can feel the presence of a loved they've lost. It could be interprated to fit with a ghost/human relationship.