Hi, I'd like to help you with your question.
It is important that your friend wants out of her situation so you can help her. If she is not willing to get help, then there will be little you can do except support her until she is ready and try to encourage her to seek help.
If she does want help, there are numerous resources to help her. She can start by seeing a therapist. She can see any therapist that has either a Master's degree or a Ph.D. A Master's level therapist will have either M.Ed, MA, MSW or LSW after their names. Some have additional licenses, either national or state level. The type of degree tells you what the therapist is trained in. For example, I have a M.Ed which is a Master's in Counseling. An MA has a Master's in psychology theory and a MSW/LSW has a Master's in social work which is the study of family and social systems. A PhD is someone who has a doctorate in those fields, mostly counseling and education.
A psychiatrist is a medical doctor that specializes in mental health related medications. Unless she is having trouble with her daily activities and her feelings are too overwhelming for her to cope, she most likely does not need medication.
Your friend can find a therapist by either talking to her doctor for a referral, speaking with her pastor if she attends church, or by searching on line at http://therapists.psychologytoday.com/rms/. She can search by zip code for her area.
There are also many resources to help her learn to help herself and recover. Here is a list to get her started:
http://www.thehotline.org/- this includes information for her and for you to help her with.
The Emotionally Abusive Relationship: How to Stop Being Abused and How to Stop Abusing by Beverly Engel
The Emotionally Abused Woman : Overcoming Destructive Patterns and Reclaiming Yourself by Beverly Engel
Emotional Abuse: The Trauma and the Treatment by Marti Tamm Loring
Why Does He Do That?: Inside the Minds of Angry and Controlling Men by Lundy Bancroft
You can find these books on Amazon.com or your local library may have them for you.
Let me know if I can help in any other way,