Tim, if I were you I would not get her father to interfere on your behalf. He may want you together and when you speak to him you can say that you want that too but ultimately it comes down to W. It is her decision and you do not want to push her. He should respect that and see that you truly do have her best interest at heart.
If her Dad decides to say something to her let him do it off his own back don't encourage it or discourage it, just keep neutral. Tell him you want to remain in touch and that as far as you are concern nothing changes with anyone else in the family.
I just think it is dangerous territory to get her Dad involved b/c W will see that a whole different way.
I know you are grasping at other option but you said it that is controlling and a bit manipulative. Let him do as he pleases but I urge you not to ask him to do it.
Let's see what the others say but that is my opinion...
