My girlfriend is still haunted by her past?

My girlfriend and i were talking and i brought up the first time i had sex. I asked her about what her first time was like and she started telling me how her father would force her and her sister to have sex and if they didn't he threatened to kill them. She told me he beat both of them and raped both her and his sister. She told me he died in a car accident while driving drunk years ago but she is still haunted by what he put her through. To make matters worse her mother died after giving birth to her and she told me he blamed her death on her. I was shocked and disgusted by what has happened to her. I suggested counseling she told me she has tried that and i doesn't work. What can i do to help her?