I wonder if he had a docile companion - actually another chick or chicken - in a wire divided pen where they could see each other but, not fight. Just having another bird around would probably satisfy him. Over time he might even get long with it - when eventually put together. I wonder if he prefers one of his own kind- another silkie but a female, so they won't fence fight.
Probably the wrong thing to suggest, I know what you have gone through with just ONE silkie, another might be the last straw. He is such a beautiful bird, it's not fair that he has so many problems to carry with him.