i attend group therapy and yes counseling too maybe talk to a doctor who can prescribe an anti-depressant if possible also :)
she should go see a therapist. please encourage her - two of my friends had abortions in high school and both ended up attempting suicide and had to be institutionalized for a significant period of time. the sooner she talks to someone about it the better off she will be.
She is possibly suffering from PTSD (post traumatic stress disorder) and should talk to someone professional as they can help her get rid of them. (I am not a professional but have been through a similar thing)
She may need to seek the help of a therapist. She may have unresolved feelings of guilt or pain related to the abortion and needs to talk them out. My sister had an abortion when she was 15. I had horrible guilt and I wasn't even the one who had the abortion, but I was the only one in the family that knew about it. I actually went to councling and it helped me very much. Good luck to your friend. I hope she feels better soon.