Wow. You are a very bright 19 y.o. And you have every right to feel as you do. It's a very sad to see someone who should be a role model deteriorate before your eyes.
Your dad is going to continue drinking until he's ready to quit. It's super frustrating to those of us who have never had the problem. If you can get to an Alateen meeting, it might help you a great deal. And stay connected through here as well. As far as the bratty part, it's completely understandable. Its a way of communicating without actually confronting him. Focus on your future and do what's best for you. Don't let anyone get in the way of your goals.