Do you mean to campus?
Often families travel together. Not an issue to bring your little brother, but he won’t go in the interview room. Your parents may want to keep him engaged outside/on campus, or playing board games. Hotchkiss and numerous others have an area in admissions where siblings can play board games, read books, etc. Your parents just need to make sure your sibling is well behaved, and if he gets antsy, they need to be prepared to bring him outside. I think it’s nice when it’s a family endeavor, and this process affects everyone in the family.
One or both your parents may also be asked to speak to the interviewer for 5-15 minutes after you are done.