Danganronpa Headcanons

I need help

I was originally going to post a head canon but I need some advice/help. So there was this guy that I was friends with and he told me that he liked me. Of course I don't like him back but after that he started talking about him hurting himself and saying that I don't care about him and stuff like that. He put me in a horrible mood all day with that conversation which he told me was a "joke" at the end. But he kept being negative. He started turning our nice light hearted conversations into more depressing one. He kept apologizing for no reason and he was making me depressed and irritable at everyone and everything. I didn't like how his mentality kept effecting me so I blocked him on every communication app. I even had to mute and report him on Wattpad. Now he's harassing my friend telling her that if I don't unblock him he'll kill himself. I feel like he's being really clingy and selfish, harassing my friend to get my attention. I refuse to unblock him. I'm getting really sick of this, of him. I told him our friendship is over and that we shouldn't talk ever again. I had my patience, he just used it all. I was nice, but now I'm not, and that's a hard thing to accomplish. What should I do?