How do I help a friend?

I (M40) have a friend (F32) who is seriously involved with a man (31) who appears to me as textbook narcissistic personality disorder. Just some of the first things that come to mind:

  1. He rushed the relationship with my friend, even moving in with her and her mother just a few months after meeting. Now, he has bought a house nearly a hundred miles away from anyone she knows well. Just his family, and his friends.

  2. He has sowed discord between her and her family members, as well as her friends. He has "forbidden" her from seeing or even speaking to me numerous times. When he finds out that we still chat, he rages. I have witnessed his verbal abuse more than a few times.

  3. He has been violent to her, restraining her when she tried to leave, etc. I won't say he "beats" her regularly, but I just don't know anymore, since my friend will no longer speak to me for fear of angering her fiance'. Earlier this year, their neighbors called police when they saw him chasing her and dragging her into the house. He was arrested, but no charges were filed after my friend refused to cooperate. He has even threatened me several times to stay away from her. (Brief background: My friend and I were once romantically involved, but have been platonic for quite awhile. He believes, wrongly, that she is cheating on him with me. I do not believe his pattern of emotional abuse is caused by me. It will be someone else, or something else, which triggers his rage now that they have moved so far away.

    Anyhoo, I fear that he will become increasingly violent, or, at the very least, continue his emotional abuse toward my friend. My friend, the last time we spoke, has begun to make excuses for his behavior, even taking blame for it, thinking that she causes his rages and abuse by not meeting his expectations or something. Is there any tried and true way to get a current victim to see this behavior for what it is? From me, she won't accept advice. Any input is appreciated. Thanks in advance.