What do I do?

So, my brother in-law stays with us for the time being, he has his kids on the weekends... he lets his daughter sleep on our couch and she left a huge blood stain on the couch this morning and just covered it with a pillow, I moved the pillow and sprayed cleaner on it to soak and went to the grocery store. I came back and the pillow was thrown back over the stain and not even an attempt to clean it up was made. This isn’t the first time this has happened, this is the third time actually, the other two times I cleaned it up and didn’t say anything, I’m not doing it again. She needs to realize eventually that parts of being a woman sucks, and one of those parts is cleaning up after yourself when you leak, especially when it’s on some else’s furniture. But how do I handle this situation without sounding like a total insensitive bitch? I mean, I already clean up after everyone and cook for everyone and they already all completely disregard our house rules because their dad doesn’t enforce them. I’m just tired of being a door mat for kids that aren’t even my responsibility.

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My hubs works away from home, he won’t be home for another month, I’ve told him about the goings on here while he’s gone... because this doesn’t happen to this extreme while he’s home. BIL has his chores and responsibilities here, he does them, for the most part, I guess it just seems like he feels more entitled to be here than I am. It’s always kind of been like this, we just stay clear of each other while his brother is away. He was supposed to be moved out April 1 but something happened with the place he was moving into. Oh, btw, I’m 34 weeks pregnant and less than nice right now, especially when I comes to things I’ve mentioned over and over again, he even went so far as to mutter under his breath to just clean it up myself because I don’t have to say something about every mess his kids make.