While going through detox, hopefully with medical support, also find a therapist for your friend, one who can support them with tools for anxiety and address the feeling that led them to needing Xanax. Therapist should specialize in anxiety and addiction issues. There are low fee agencies in most areas, if they can’t afford it. Also Check out The Mood Cure Book, by Julia Ross, or other books on natural brain healing. There are nutritional supplements that can help with the anxiety while detoxing.