Welcome to SR, Strawbz. To be honest, it doesn't sound like he is relationship material at this point. He has scads of problematic issues in addition to addiction. He seems to be hung up on his ex, he has attempted suicide, he runs hot and cold with you...saying he wants a relationship, then getting upset and blocking you on social media, then coming back the next day wanting to talk. Frankly, it doesn't sound like he knows what he wants. These things are all huge red flags, and that's before you even add in the addiction.
I agree with doggonecarl that you should look at what all you wrote and, taking the emotion out of it, decide what you would tell someone you care about if she were in that situation.