I do not know the story, but this light novel also had a drama live action movie, which was korean, my friend watched it and told that since the light novel was ongoing they had to provide a conclusion there so in the ending of that she passed away due to cancer or something like that which was sad, currently in the light novel she is well and alive but the author just don't give it your lie in april ending man pls (and yea this doesn't count as a spoiler)