I actually like how there's a little complexity to the backstory of the curse where you can kinda blame everyone at least somewhat. Makes it seem like resolving it won't be very straightforward.
Honestly the ambiguity in this one isn't even that bad imo, it kind of feels appropriate from the perspective of the outsider bf looking into the family. Like it makes it feel more real in a way. Plus it's still pretty sad even without "getting" it.
The wording of "cognitively contaminated" from last chapter sounds to me like once your brain is infected, the actual physical parasite doesn't really matter and you're doomed no matter what. It's literally and figuratively a "brain worm" that's just going to remanifest itself.
Yep it is, and I doubt Shoichi is actually there. Anai is lying to cause internal strife in the Toushou and using getting tortured as a way to make it believable. So yeah, it's convenient for the police and part of Anai's greater plan, maybe