It's so hard to enforce tough love but you have to set your son free so he can grow up. We just gave our 20 year old an ultimatum. He was also diagnosed with anxiety and depression and there was some drug use also. He is thriving now and happier. Who knows the outcome but no one knows what the future brings. I am so happy we did SOMETHING other than what we were DOING that wasn't WORKING for any of us. Least of all him. By coddling him it sends him the message that you don't think he can do it. That's what we did. Don't waste any more time.
You'll get good advice here. This forum is WHY we were able to do it and we are very thankful for all the knowledge that is shared here. Good luck. I know it's the hardest thing you'll probably ever do in your life. I learned on here "nothing changes if nothing changes". Keep repeating that to yourself. I know I did.