I am so sorry CopperStar, growing up that way is horrible for any child and should never take place. It is no wonder there is a very confused part of you. You were the only friend your father ever had, he could never be your father because he never grew up and became an adult mentally. I am sorry you grew up with that, you handled it the best way you knew how, after all you were only a child so you related to the part of him that was a child that never grew up until you matured and he could not. That child part of him that was a friend to you was gone a long time ago. He was terrified of growing up and feeling so he self medicated and that just took away whatever had been there. No, he doesn't want to get better and his brain is now incapable of it, he has been like that for a while now and that is why he leaves every place that tries to help him in any way.

It is really up to you whether you try to find him to see him one more time or not. Mentally he probably doesn't have much left, it sounds like he just wants his own space, even if it's in his car which he prefers rather then being put where he is with other strangers.

I think the only worth while parts of what your past was when it came to him are those positives that you remember, it's ok if your mind choses to put aside whatever is not worth remembering.