Markus,
Great job deciding to quit while you are still young! I started using nicotine around the same age as you, so I definitely understand where you are coming from. I am 23 now, and trust me, it doesn't get any easier to quit. Today is always the Best day to quit!
You need to read the Welcome Center and fully understand what it is we do around here. In short, we post a promise not to dip for the day, and we keep said promise. Sounds simple enough, and it is, if you're not a caving douchenozzle.
Again, congrats on your decision...now let's see that big Day 1 in November!
CC
P.S. You can not make anyone (your brother) want to quit, they have to decide that for themselves. Trust me, I tried the same thing. It does not work and it can potentially derail your quit...so, just worry about yourself and be an example to your brother. Maybe that will inspire him.