Such abuse can leave the survivor feeling that no man could ever truly love her. She may become very promiscuous, searching for love in all the wrong places. Depression is also one pretty sure potential; even bi-polar disorder has been triggered by such abuse. As you know, she has learned to hide her pain well, hopefully you and your family will be allowed to help her release it in a healing manner.
Solly makes an excellent point - "She had a safe place to go to..she saw a family where the Daddy was a Daddy and not a monster. You don't realize it now but that was a big help to the child.". Far too many survivors are never fortunate enough to be blessed by having people like you and your family to lean on.
Having a caring and decent male figure in her life was a much needed gift that you didn't know you were giving her. You have shown her that she has value and deserves respect. I'm sure you have given her hugs now and then over the years, it helped her see that a man can touch her with love; not just lust. I cannot begin to tell you how much that can help a survivor of such bullshit.
As enraged as you are, and I'd like a shot at that creep myself, you will do her much more good if you can stay in her life rather than in jail.
Bless you and yours for giving her such a gift.

I wish someone had been there for me many years ago. Still hurts too much at times.
And be damn careful with that ax; sharp things and the distraction of anger can cause nasty accidents!