Hello,
I have no great insight, although I am in a similar situation. My boyfriend told me he had ptsd very early on in our relationship, but I had no idea what it was nor did he show any symptoms. His is combat ptsd from military service. Anyway, he was quickly able to express his love and say "I love you" way before I could. We had a wonderful, symptom free 8 months. Then at the end of January he went into a downward spiral with his ptsd. He says he is not good enough for me and that he is destined to walk alone because he is no good for people.

I have just encouraged additional treatment....he already takes meds and gets a tiny bit of counseling. And I also let him know that I am here for him even though he is pushing me away. That is about all you can do. They have to want to get better. You can't make then want to get better.

Just encourage him to get treatment and let him know you are there.
Good luck to you.

Sisu