Well, while we were given a glance to the future about how only 2 remains and all, i do think, it could had used a better closing, maybe Reimu seeing their babies "somehow death" mourning and shit, and then making sure the remaining 2 would take it easy, etc....
When I first read this story I did not realize how much trouble this family was in for wanting children during winter, let alone 16. Yukkuri eat the most when they are growing, and they take 3 months to reach full size. That is all of winter. A food supply that would be more then enough for two fully grown yukkuri would never feed a clan of 16, and even only 4 might be cutting it too close.
Marisa did exactly what she had to. Reimu is already showing the signs of turning full shithead.
Now she has to take of 16 shitspawns born from a Deibu? Fuck that noise. If i were him, i would fucking kill the mother Marisa becomes a bullied husband.