Apparently in Japan there are really rent-a-someone business and it is legal. Most popular are renting boyfriends and little sister.
I'd also like to add that there's people who also rent families, boyfriends, and girlfriends as well! Not to mention the rent a sister service can also be used as a way to help himikomoris come out of their shell and such. There's a lot of reasons people use these services(a few people are using it as a way to experience having a family again after loosing them as such) than just the way a lot of manga makes them out to be(for romance and such). It's quite interesting and I think there's a few videos explaining this phenomenon.
wait... do people actually rent someone to be a brother? also did he think he was call boy/hostess