Wtf are you guys talking about?
You brother comes up to you with TWO BOTTLES OF JAGERMEISTER. THEN ASKS FOR WEED. Are you that friggin' blind? I was a little different when I was around that age, I loved being carefree and young, but I also wanted to taste the forbidden fruits as soon as possible, and know all about these things. I also knew that there was no way anyone in my family could know of my personal intentions, becuase then suspiscion would arouse and I'd have less of a chance to be free.
It all depends on the individual I guess, but I was a little brother. Theres no way in HELL I would have done what my older brother told me, in fact, I would have done the EXACT OPPOSITE. You're not an asshole at all man, you're doing the right thing, but trying to advise him and chastise him is only going to get you the opposite of what you want, if he's like me at all.
The one thing that I would do, is explain to him all about puberty and brain chemistry and the effects weed and alcohol and even caffeine can do to young people. Don't tell him not to do it, or give him fake shit, that's just bs. Tell him you understand he's going to make his own descisions whether you try to excersize your "brotherly control" on him or not, but that there are serious consequences if he does, things he has no idea if he'll regret later in life.
I had the oppurtunity to be "educated" about weed by my oldest brother, around 12/13, and I didn't become a tweaker, I didn't even become a stoner until I was 15. I understood the consequences (becuase my brother actually respected me as a human being and realized I was his BROTHER not his KID) and decided to wait for a bit to smoke more.
But if he walks up with two bottles of jagermeister... and then a few seconds later asks for weed... I just have a feeling he might already know what' he's doing. If that had been me, I would have.
But I was (and always will be) the most curious ass on earth...