@Glara, I have been in your position before. And it sucks.
But at the end of the day, you can't let someone else's actions hold you hostage. Why? Because you know that if they were well they would never want to hurt you like this. Because you don't deserve this. Because you can't make anyone else do anything. Because he is choosing to distance himself and not get the proper help he needs. (Yes, he is sick, but he is also not choosing to actively fix what's wrong.)
But at the same time, you are choosing to have this drama in your life, he isn't making you choose it. We all can tell you all of these things, but you aren't going to move on until you're ready, because we can't make you do anything either.
However, if he knew how much pain he was putting you in, he would probably hate that he ever got in contact with you in the first place. But, if you continue your life, while also letting him know that you are there for him (but are not going to contact him first again), you will be putting him at ease. Telling him that you love him but will not be contacting him first again makes him in control of your conversation, yet also allows you to go live your life and be free of this roller coaster. Worrying does him no good, it only will make you hate him the longer it goes on.
If you want to put both him and yourself at ease, trust him to do what is right for him. Although it's a giant kick in the arse, sometimes real honest love is letting go because that is what is best for him, no matter how much it may be tearing you up inside.