sorry. I can not imagine that.
If it were me, I'd sit next to her. Hold her hand. Make sure she knew how much I loved her and then tell her that whether it happens in a day or a month that she is dying. Id make sure she knew how honored I was to be her father. How she is the light of my life and I will miss her every day until I see her on the other side.
I would probably try to keep my emotions together but I would probably just sob, hold her, laugh and make sure SHE KNEW how much I loved her.
Prayers brother.