It’s still not working and the old topic has been closed.
Fixed in v.27 Bug
As a workaround, your bother can still add people if he asks those people to add him to their list (so the invitation is sent out by the other players, and not your brother).
Thanks, it works, but I’ve already received this bug medal in version 25.
You received a medal for reporting the first bug, which was (incorrectly) fixed. Now that you re-report that it’s still not working, you get another medal.