faithfull, you are not to blame for his situation. you can only do so much. so far, you've done what you could to help him but unless you are working in the medical field, how can you help him like he needs to be helped.
i'm still curious to know if you have actually heard his doctor tell you his diagnosis or is it him who is relaying his doctors messages. i honestly don't believe that god will punish you for stepping aside and allowing him to get to the place where he wants to seek help for himself. you don't have to leave forever, only one day at a time. you never know, this may be what will drive him to seek recovery. please don't continue to except the blame for this, i'm sure if you could fix the situation, you would.
remember, while you were not there to help him, he sought help for himself. i think even if he ended up in the hospital, they will have to have permission to treat him and they do call in specialist when needed, don't they?