The Elder Hanagaki

Takemichi has an older brother, Takehiro (OC) who is 4 years older than him who just got home from South Korea after graduating high school and enrolls into Tokyo Revengers Academy as a Teacher. when Takemichi gets into a gang fight and gets beaten up, his older brother step in and saves him but he will get involved in a gang affairs again in a process after he retires in his gang life. what will he do? how will his older brother going to handle those affairs when he chose to get involved again?