AIO my friend left after I disliked a joke he made about me

I (18M) had this friend, I won't specify him. Just a couple months ago we were really close, then I developed a very rare branch of schizophrenia after an extreme depressive state and he found out months after I'd developed it. I tried to hide it from him, I don't know how he found out but he did and texted me saying that *if I ever needed to vent, he was there for me*. Fast forward and we were talking (I don't remember what about) but he made a joke about something really traumatic I went through in the past, I told him that the joke made me EXTREMELY uncomfortable and then he left and blocked me. I couldn't tell if he was playing a joke or not so I tried contacting him but nothing. Five days later, he texted me from a different platform saying that he was sorry he "couldn't fix" me and that he'd tried so hard to "fix" me but he just *had* to accept there was "no hope" for me. Saying bullshit like he just couldn't bear the thought of *giving up* on me and so he was holding out until he finally had to come to terms with the fact he *COULDN'T FIX* me. I won't share the screenshots because they contain personal information... but what the fuck? Why would you say that to someone?

I NEVER vented to him about it because I didn't want to put weight on his shoulders. I always let him vent to me, I cared about him and that's what he says? "Not that you ever actually cared about me anyway." What the fuck?!! And, I'm not the best person, never said I was, but seriously. He left because he couldn't *fix my mental health disorder and erase my trauma*. I texted him back APOLOGIZING for saying I was uncomfortable. Then when he tried to tell all my other friends some really gross and untrue shit about me, victimizing himself so they'd leave me, I went off on him and publicly called him out, spilling some (*really bad*) dirt about him that he only told me. The dirt I had on him was insane too because it was all stuff he condemned other people for. Am I overreacting and was that a shitty thing to do?

TLDR: I developed a rare branch of schizophrenia, my friend said he was there for me, he made a joke about a traumatic thing that happened to me, I told him the joke made me uncomfortable, he left because he couldn't "fix" me and there was "no hope" for me. He tried to make my other friends leave me by spreading rumors, so I publicly called him out and revealed the dirt I had on him.