Should I tell this girls parents how their daughters behaviour is impacting my husband

I am supporting my husband who has PTSD. Lately he has become insulting, emotionally abusive, has forbidden me to speak in the house,locks himself in the study for hours on end having facebook conversations with a woman he met at the local RSL and violent on occassion. He is under the care of a pyschologist but she announced last week that she thinks he is fine and no longer has any problems or anger management issues. The only thing I can interpret from this is one of two things. Either I am imagining this and he is fine and I need help, or (what I think has happened) he has been putting on an act for her and she only sees the side of him he wants her to see.

I am a full time postgraduate student. His behaviour is impacting my studies as I go to uni hours before I need to as I am constantly frightened at home that he will turn into one of his rages. Also the study he locks himself into is the where the computers, printer books and stationary are so I often cant access things I need

I have spoken to counsellers before but their advice has been just leave him but it isnt that simple. I dont have a job, I have no money or family or friends (he has alienated even his family members with his threats of violence and insulting manner) so I have nowhere to go. He was getting better before he met this girl but now he has become paranoid that people are 'out to get him'. I say girl as she is 27 years younger than him. She has been diagnosed with multiple personality disorder. She has broken up with him twice since ANZAC day. Everytime she does and he is out of her influence for a week or two he starts to get better, and even begins to think about the hobbies he used to have and how he can get his friends and family back. Then she returns , says one of her other personalities broke up with him, and then we go back to the dark side of his personality again. He is now constantly worrying that she will find another boyfriend, is constantly on the phone to her, spends hours on facebook in chat sessions with her and his doctor now has him taking multiple doses of hypertensives as his BP is going through the roof due to his constant anger)and I am at my wit's end again. He just went out again with her and said he might be home tonight and not to try anything stupid like contacting his psycologist as his girlfriend says he doesnt need a psychologist.

Do you have any advice as to how I can improve the situation? I can see there is hope for him if he can just break his ties with this girl. In the past he has begun to improve, I dont want him getting into trouble with the police etc as he was not like this before the PTSD. She lives with her parents and I tried speaking with them but she had told them he is not my husband he is my brother and they simply see me as a jealous sister. Also I think they feel that if she is out with him she is out of their hair for a while. Has anyone had a similar type of situation that could advise me as to what to do. I feel like I am on an emotional rollercoaster.