You can only sponsor your brother if you have no other relatives living with you and your parents are no longer alive. As long as your parents are alive, you cannot sponsor your brother.
However if you sponsor your parents as PR in the new year, your brother can come as a dependent of your parents if he is 18 or younger at time of application submital.
your answers are always right on point, I'm starting to think a lot of the questions people ask are absurd. "Can I sponsor my niece, aunt or uncle, a friend of an uncle or my school friend from the next village... etc."