Wow. When I started reading your post I thought for sure you were going to be the WAS, I'm really surprised that your H was the one that walked. You must be truly incredible to want to keep the M together after all you've been put through, I really admire you for that Let's look at your husband:
- He is in severe depression - He quit taking depression med's - He has chronic health issues - He's been hospitalized for being suicidal - He's verbally abusive - He has anger issues - He smokes pot and illegally takes prescription drugs - His attitude is getting worse
Now let me ask you, if your best friend came to you and described her husband this way and asked you what to do, what would your advice to her be? Your H has major, serious issues. A great marriage is simply not in your future unless he seeks out professional help on several fronts. He needs A/D meds, he needs counseling to deal with his anger, depression and abuse, and he needs intervention/ rehab to stop the illegal drug use. Since he left I can only assume he thinks you are the problem, so you can't help him. Any attempt on your part to steer him to help will appear to him as pressure, nagging, etc. You have got to detach in a serious way, not to get your M back but to improve your outlook and get your life back on track. Leave H to resolve his issues on his own for now.
Normally DB recommends not soliciting help from family/ friends, but your sitch is different for the above reasons, and if it's possible to get someone to talk sense into him then you really should try. Not to try to steer him back to the M, but just to get him to get professional help.
Let's look at your husband: