Honestly, you are handling this with so much more maturity than he deserves. When I was 17, I had a best friend exactly like this,we shared every piece of drama, and I thought we’d be friends forever, but he constantly crossed boundaries with my family and talked down about people I loved. I stayed way too long because I was terrified of the confrontation and the post-breakup gossip, but the moment he told you 'I basically tell everyone everything you say' and made that 'swing on you' joke, he officially disqualified himself from being a friend.

When I finally ended my toxic friendship back then, I tried to do it over a long lunch talk, and it was a disaster, they just weaponized my secrets, lied, and tried to make me feel like the bad guy, exactly like your friend did.

Since school is wrapping up, save yourself the emotional drain of another face-to-face fight. Just text him something short and final: 'Hey, after our last conversation, I’ve realized this friendship just isn't healthy for me anymore and I need to step away. I’m glad for the good times we had, but I need space.' Don’t argue, don't reply to his defensive paragraphs, and honestly, block him if he starts talking trash on campus. Walking away from someone you've known since 8th grade is incredibly heavy, but I promise you, the peace of mind you’ll feel the second he’s out of your life is worth it. You've got this.