Thanks for the translation, nice to see this again.
I think he was acting a bit too over the top creepy in this chapter though to be honest. At least try to be normal about it my guy.
Tbf, he never said there's anything wrong with the family, just that he feels uncomfortable with them. That's his own issue that he needs to work through, but I think that's valid.
Isn't the solution staring us in the face? Change the witch girl's little sister to be the MC's little sister.
Sure, it would still be fucked up in terms of the little sister's free will or whatever, but it's better than killing her.
I feel like it must be Stomp, that was like late 90s and they used all kinds of things as instruments, so it would fit. They're brooms not mops but maybe it got lost in translation.