I just read her other work "Mikkigan demo Genki desu 38-sai" that chronicles her experience as a cancer patient. She also mentioned that she was abused when she was younger, so that was even more heartbreaking.
The manga ended on such a hopeful note, but now knowing that she passed away, the manga has become very bittersweet. My condolences to her surviving loved ones like her husband and in-laws. I hope they're all doing ok.
I just did as well and while I can see how others would see it as hopeful I saw it as her in denial that she was about to die (very common in stages of grief). She said in the extra/bonus that she was about to reach her limit of chemo because her liver enzymes and white blood cell count were getting too high, and had convinced herself that she was no longer terminal simply because her treatment was actively killing her cancer cells, even though she probably still had a lot, she wanted to believe she was not going to die. A part of me thinks she just didn't want people to worry about her.
It really killed me, I even looked at her Twitter, the last thing she posted about was eating strawberry ice-cream. I'm glad she could still live happily until the end. Her husband seems to be coping well or at least that is what he decides to tell people.

I love a good BL story in a historical setting, and the reference to Japanese folklore was quite the learning experience. The art, of course, is beautiful, which is what got my attention into this manga in the first place. I felt the story was a bit rushed, so I was hoping there would be more because a one shot just doesn't do justice.
Unfortunately, the manga artist had passed away about a year ago, due to cancer. May she rest in peace ;_;