I am so sorry to hear this, but all I can do is offer prayers for your Dad and you and the entire family.
Cancer is probably the most dreaded diagnosis anyone could be dealt - not only for the patient - but for everyone involved. I know it's easier said than done, but please try to be strong, no matter the outcome. You have that little person just starting her life, that needs you.
Unfortunately, I've had to deal with this dreaded disease with family too. My father, grandfather, and 2 uncles all passed away with cancer, and both of my brother have had it too. It never got any easier to accept no matter how many times I had to face it.
Just know that we all have you and your Dad in our thoughts and prayers.