RE: Visiting my brother and made him him a (silent) Steemian. I'm currently looking for ways to give him some ROI on his investment.

[captaincanary]

If he delegates his SP to you he will get a ROI right? I'm not sure about how it works. If not he could just come on Steemit occasionally (once a week or something) and upvote a few posts he likes. Even if he just leaves it in SP and does nothing he will earn a small amount of interest.