Me and my boyfriend have been dating for about 2 years, and although i knew that he had depression even before we started dating, he was a lot better back then than now. I've noticed his symptoms have been getting really out of hand, and i even had talks with him where he honestly said that sometimes he just feels like ending it. Now here's the thing, i knew about this and I've always been supportive and reassuring to him, and he himself went to therapy even though he said it didn't really help, and I'm at this point where im really scared for him and its making me anxious 24/7. He's been diagnosed with clinical depression for 4 years now, and like i said, it was never as bad as it is right now, and he's been hinting that his hope in recovery is getting slim. I will not leave him no matter what, it's important for me to get him back to a healthy mental state, to get rid or at least lessen his suicidal thoughts, and i need to know how to do it even more effectively. Also, i just really wanna know how do people get out of situations like these? He's been abusing weed and alcohol on top of his depression and I've been really trying to make him stop but at this point I don't wanna make him mad because he doesn't like people lecturing him on how he's supposed to cope/ feel something. 
He's tried a lot of things that are "supposed" to at least help, and yet he says they don't, then what can we do to get him better help from a medical standpoint? Any advise is highly appreciated.