I never realized that some people here think that there was a real daughter because the story *very clearly* established that the entity works by creating a false dead child and then feeding of the grief. That was what made the story so effective to me.
I haven't listened to it in a while, so I'm not sure why I missed that. My guess is that the firm clues were all at the beginning when I was still trying to establish the setting, premise, speculative element in my mind and lost some important details in the struggle to form a cohesive setting. That could likely change what I thought of the story, though:
1. Scattercat's last comment about how it's odd that no one else noticed their grieving of an imaginary child doesn't have an obvious resolution.
I'm not sure about that. The grieving was done at home. I don't think the entity made them feel like they just lost a daughter. It made them feel like they had lost her long enough ago that the grieving had become a private thing. They probably felt "oh, we never talk about our daughter to oursiders, since that's too painful" - and quite possibly, the entity makes them withdraw and avoid contact with society. A lot of their reactions to the narrator - the "we accepted the facts, please don't reopen them" makes it sound like they feel like there is a reason to avoid bringing it up with strangers and most casual acquaintances.
Those who are closer to them and spend more time with them, like the sister, might feel something is amiss, but the more time they spend in the house the more they, too, will fall prey to the entity. My guess is that the victims will either cut off ties with anyone who insists that they had no daughter, or bring them into the fold.
I think that that's the reason the "the daughter is alive" strategy works - the entity is protected against direct attacks. That tactic takes its lies (specifically, the existence of a daughter) and turns them against it.
2. And, regardless of whether the child existed or not, I'd still say that there's not much obstacle to the protagonist's progress. He is confident that the solution will work, and it does, like it has before. So it still lacks dramatic tension.
As I said above, this is a criticism I basically agree with. Not entirely - I wouldn't say that the story completely lacks dramatic tension since we, as readers, don't know it will work. But the dramatic tension is definitely considerably less than it could be.