Firstly, I hope she is appropriately protected and safeguarded, and that she is able to access the long term psychological support I can imagine she may need.
Secondly, our prison system is broken and fails to rehabilitate, it just causes more damage. It is never going to succeed in rehabilitating people other than a few exceptions in its current set up. Six months or twenty months, he still would not have left prison "reformed".
Thirdly, prison is not for revenge, so sentences are not passed to facilitate the psychological healing or closure for victims. I doubt there is any sentence he could have served where she would have felt fine about his release, not after the horrific things he did to her.