Your friend has my deepest sympathy and I hope that CAF's members will join us here at Catholic Answers in praying for her recovery. If she is not already seeing a counselor, I urge you to recommend to her that she consider therapy with someone trained to help victims of sexual abuse recover from their trauma. She might contact the Pastoral Solutions Institute
for a referral to a counselor in her area.
Most of the suffering human beings endure in this life is not specifically chosen by the person as something that he or she desires to endure. Because God gave human beings the gift of free will, a consequence of that gift is that some human beings will choose to abuse it at the expense and suffering of other human beings and of God. Without free will there might have been no human suffering, but there also would not be the possibility of love -- either for God or for each other.
By choosing to incarnate as a human being, God chose to enter into human experience and into human suffering. He chose to allow himself to be betrayed, abused, and put to a shameful death, not because he is a masochist, but in order to redeem humanity and to give suffering redemptive value. He does not intend us to seek out suffering, of course, but the suffering that we endure does not have to be meaningless. If we offer up that suffering, God can use it for the sake of others.
Perhaps your friend might offer up her suffering that God might give another potential abuser the grace to overcome the temptation to abuse an innocent. Or perhaps she might offer up that suffering for the sake of another intention close to her heart. The choice is hers because God gave her that gift to transform the evil she endured into something that might protect others from suffering as she did.
St. Francis De Sales
once said on the subject of suffering:
The Problem of Suffering Reconsidered
The everlasting God has in his wisdom foreseen from eternity the cross that he now presents to you as a gift from his inmost heart. This cross he now sends you he has considered with his all-knowing eyes, understood with his divine mind, tested with his wise justice, warmed with loving arms, and weighed with his own hands to see that it be not one inch too large and not one ounce too heavy for you. He has blessed it with his holy name, anointed it with his consolation, taken one last glance at you and your courage, and then sent it to you from heaven, a special greeting from God to you, an alms of the all-merciful love of God.
by Peter Kreeft (article)
Why Bad Things Happen to a Good God
by Fr. John Dowling (article)
Did Christ Have to Suffer?
by Paul Thigpen (article)
Making Sense Out of Suffering
by Peter Kreeft (book)
The Problem of Pain
by C. S. Lewis (book)