I think it was the adopted mom who framed the mc and wants to kill him rather. He knows that the mother is a killer thus, a way of silencing him is to do that hmmm. Or the ml is just a 100% asshole.
It has this part wherein there is three childhood friends. Two of them both like the same one, the third childhood friend. They also like getting hurt. I think it is in high school settings too. The MC, the third childhood friend, thought that he was being left out since he saw those two kissing.
: "Don't tell anyone"
: "Takes a picture with everyone (and a famous actor too)"
Yup, just to keep the story going