Hi, beachyearner;
Welcome to SR!
Have you tried WebMD? They have multiple forums.
Also, if your friend is anxies and depressed due to coming off of the methadone, then, the substance abuse forum or the NA forum here would be appropriate. We even have a secular forum that might interest him, depending on his philosophy.
I do hope he recovers from his problems. My prayers for just that.
Shalom!