I have a niece who is an adult now. She confided in me that she was horribly abused by her own father, uncle, and half brother when she was a small child. The sexual abuse went on for years. Her pain is real. She cries a lot. She wants to know why?…Are they sorry for what they did?....
You are seen as a teacher of wisdom.
Explain to your niece that since she has been living on a daily basis with the thoughts of the horrible things that happened to her for so long, most likely she will need professional help.
However, since you ask for my advice: explain to her that every time she thinks about what those evil people did she is, in effect, allowing them to do it to her again.
Instead of living with the torture that she herself is now allowing to come into her daily life, whenever those thoughts surface she should train herself, even force herself, to have at least two pleasant thoughts. She should think about nice things that are going on in her life today. She must teach herself to be thankful for even the slightest positive things that she has right now: no tooth ache, no medical operation scheduled, she has food to eat, she is able to walk without a wheelchair… and on and on. She has to spend her time thinking about the pleasurable things that she has now.
Otherwise, as I just pointed out, she will go on living with her abusers in her house for the rest of her life (G-d forbid).
Most of what we experience in life is determined by our thoughts. Our moods, our mindset, even the wrinkles on our face are shaped by our predominate thoughts. As the old Yiddish saying so wisely teaches; "Think good and it will be good."
Hashem bless your niece with a wonderful, joyful life.