Mrs. Asaka died of the same disease that Kaori is suffering from.
It's possible that Kaori's condition was passed down through the family, and it could explain how she got it. Unfortunately, this would mean that Shiori has a chance of getting it.
Seri and Ruri are a couple.
Seri is quite close to Ruri, to the point of slapping Shizuku for bullying her and calling out Kaori for asking Ruri to meet with Shizuku. Additionally, Seri not only appears to have nothing against lesbian relationships, but assumes that Shizuku and Kaori are in one, and since the scene involves her making a "Not So Different" Remark regarding herself and Shizuku, one could assume that she's also in love with Ruri.
