Asked and answered: a subsequent entrant visa is for a Member of the Family Unit (i.e. spouse or dependent child) of someone who holds a Skilled Work Regional (Provisional) visa (subclass 491) visa (which your brother doesn't, even if you were a member of his family unit ... which you are not).Hi, I wanna migrate Australia under 491 - Subsequent visa category. My brother is a 189 visa holder and already have the PR as well. So he is willing to sponsor me to migrate. In this case can someone answer me if I can apply under 491 - Subsequent visa category which says "This visa is for a member of the family unit of someone who holds a Skilled Work Regional (Provisional) visa (subclass 491)"
So, in summary: no, this visa is not for you.