
I think it may be the brother was "obsessed" with ML because eof that toxic family and when ML started getting close to MC in their highschool years, the brother tried to "drive off" MC, but MC couldn't help his feelings for ML and the brother caught them kissing or something so the brother did su*c*de and the MC thinks it was his fault..? Or maybe no self death but the brother found out and ran into traffic and got hit by a car, and the MC was like "omg how could this happen" and the brother goes "this was your fault" and dies.
Either way I don't think it was an incestuous relationship between ML and his brother.

I could see that too. Smth like the brother was sickly and sheltered and kept away from the outside world so when he met MC that treated him kindly he became obsessed with him, but MC liked ML and brother became jealous and did smth that resulted in serious injury/death and blamed it on/ guilted MC which caused him to run away from ML.
Dear OG Santa
ID NEVER FORGET YOU OG SANTA, I START PLAYING THE SANTA TRACKER ON DEC 26 AT 12:00:00AM. thanks for the Xmas gift (this ch.), stay safe, love you lots, and I'm in your walls till next year.
Love,
Your mom