Let me begin with this: this is not my story.
However, someone I love has a second personality. He has been to a few therapists, who have not helped.
Luckily, there are only the two of them. The main, and the second. When he was younger he would often black out and later be told what he did or what happened. In fact, before a certain age he doesn't remember anything at all. He has no idea what might have caused this, as he has no memory of it, and his second won't reveal it if he knows.
Those that knew him when he was younger also won't tell him if there was anything that occured.
Unable to locate the cause of the split, he is also unable to merge with his second. His second is extremely violent, and has been known to break furniture and even attempt to harm others.
After 4 failed therapists, he doubts how much therapy can help him, yet lives in fear that his second will again take control as it did when he was younger and hurt someone he cares about. To the point that he has become afraid to sleep for fear that he will not wake up one day, but his second will.
I am trying to support him as much as I can and encourage him to eat and sleep as much as he can feel comfortable to keep his strength and his health, but I'm not sure what to advise him towards. I know therapy has helped some, but after 4 therapists I'm not so sure for him.
Any advice?