wow you're fucking retarded kid. Jesus. I'm fairly sure that in the united states teachers are required to report something illegal like this. Doesn't matter that your bro has gone through shit, it's a reference (and obvious admittance) to participating in an illegal activity. Wellness Councilors can't report such a thing unless they believe it to be self harming, but a teacher has the rights of "In Loco Parentis" and is not bound by the same guidelines that a Councilor is.
from wikipedia:
First, it allows institutions such as colleges and schools to act in the best interests of the students as they see fit, although not allowing what would be considered violations of the students' civil liberties.[1]
last I checked, smoking pot isn't a civil liberty.