People are way over reacting to the sister. The sister is an idiot, on pretty much everything she does, but I really doubt she is serious about what she said at the end of this chapter, she's just shocked is all, chill out people.
Also for
@Azsy @MiiaBestWaifu @BlueOnAir @need4speedrazor6 and anyone else saying she was going to be a prostitute or get raped. WE as the audience know that, and anyone with street smarts knows that. But the sister, you can tell by how she acted, she did not know that. (And some people in the comments section didn't know that either obviously when they were complaining at why the brother was mad). It's obvious that the sister knows just about nothing of the darker things in the world, she didn't even realize what an 'adult toy company' was at the start. So she definently didn't realize how bad a situation she put herself in. Which is probably why bro was so mad cause he knew she didn't think things through.