you have to make sure that you and your brother have the same version on smash 3ds, otherwise, you won't be able to connect locally and online, for smash Wii U in order to play online,it needs to be in the latest version, so make sure you get the update downloaded before you play locally. i have that same problem when i first try to play locally with my friends at school and i told them to download an update, but since they don't have internet,they give me their smash 3ds game (i told them to put their name tag on it so that i don't get confused on which game is mine or theirs) so once i updated their game and we play smash all day long.