If your brother uses Steemvoter.com or Steemauto.com to automatically upvote your blogs (or other), he will receive curation rewards. Maybe not very much, but still.
Other option: rent out his SP (for example on minnowbooster)
Best option: actually post something now and then. Don't have to be full blown blogs, just read here and there some posts and comment sometimes. That would be highly recommended.