Do I tell my Parents about my brother drinking?

Being in high school myself, all I can say, is that it is his own life. If the drinking gets bad however, and he starts making very bad decisions, like failing or skipping school, I say tell. But for me, I drink, not like on a weekly basis though, but am still getting good grades. At my school, about 80% of the students drink. Many still do fine, and even one is our school president! In my opinion, it's how it affects him. If it's having a bad effect, then do tell. If he's able to handle it, let him. Because in college, this sort of environment is definitely something to get used to, so why not subject yourself to it now?