What do you think about me requesting my brother's friend use a separate chat for magic set up that doesn't include me?
Is it because you don't like to spend time with your brother's friend chatting?
Yes, I'm sure he'd accept my request.
I guess it's ok if you don't want to chat with your brother's friend. I hope he won't include you in his chat session.
It's fine, I'd just hide the chat.
It's okay to let your brother's friend know how you feel about the chat request. Doing this will help you to not be placed in an uncomfortable situation.