So he was simply the victim of a bitch that used him to prop herself, I imagine the novel explains her plan better but here we can guess that she asked MC for advice in how to get close to the pimp, they were alone when it happened, she took voyeur shot of herself and then proclaimed MC forced her, no proof or witnesses so it was her word against his, she gone to desk neighbor for help so to be supported as he is a good guy, but naive, he decided to denounce the crime to the whole school, tarnishing MC image, that caused a buttefly effect of his fatehr getting fired and getting a job like taxi or something, probably tired and stressed he made a mistake and killed a passerby and himself, the family of the girl sought revenge and killed MC mother, MC and his sister were alone and both were bullied and the sister seems to have killed herself too.
So MC unable to bear it anymore killed himself too, without even leaving a letter seems and with shoes on, he jsut was done with life.
All of this because a bitch wanted to get close to a guy with a "poor girl" story, crazy sow.
Unsure if ice princess kept her memories, still soon to say.
Now it would be easy for MC to stay away from the drama, if the bastard tries to ask for "help" again he will have to hold back strangling her and responding that when he is the idiot neighbor they aren't friends, maybe that using the rich dude would be a better idea, so if she tries her trick with him she will get screwed over, or both will fall (jock didn't do anything evil for now, but he seems pushy and annoying so I feel the author will put him in a bad spot soon or later).
Okay, I checked the other posts, I was pretty close, as I thought the manga adaptation skipped several important details, like MC being framed with his own phone.