The white ghost can't be Kensi's father but she does know him. She lost her father at a young age so the man aka white ghost was probably a father figure for her like a training officer or something. What I'd like to see is her freaking out about this and then calling Hetty for moral support and simply opening up.
I'd also like her to get into some deep trouble so that her team (Sam, Callen, Dicks, and the geek couple) goes dark. Just like when they went to prague. But this time Afganistan: Everybody goes home.