Yes Your parents can get a green card with in 6 months if everything goes smooth. I think have your parents get a green card and apply for your brother later. Yes I130 is the first step for this process. If your parents are here then they can apply in one package. I130, I 765, I485, I693, G325a, I 864. Please reach me at 7038488855 or 703 6262769 for free consultation. I am with immigration law firm. Thank you.