Honestly reading these in order (since I just noticed them), you can notice ALL the red flags with the mother. From her reaction in the park, to Kaede's face in Ch10 page 2, to even the drawing of the 3 in the bottom left of that page.
Reading it again, I noticed something odd: The chain. At the length it is, she normally wouldn't be able to get very far from the bed (At least without dragging the table everywhere). Yet as the story continued, we saw that she was able to get into the kitchen...I wonder if the chain is more of a mental thing then a physical one.
I did do some looking at the other raws from this Anthology and every single story doesn't have a male character, or at best, they are a faceless rando who is in the background. So this story sticks out compared to the rest...by like a lot.