Dude, it will not be easy to convince the Embassy to grant visa to your brother. Several students have tried that in the past with very less success. I know that your parents will most likely get visas without much hassle. However personally, I don’t know anyone who has been successful in persuading the Embassy to grant visa to their brother/sister so that they can guide their parents to USA and vise versa. You can try, but ‘Aash Garnu, Bhar Naparnu!’