AKANE
Kanade issued an apology in private, and insisted that she didn't think their grandmother would go that far. That she is sorry about losing her nephew. While she listened to her sister speak, all Akane could think about was laying on the ground clutching her bleeding stomach. The child, the child that she didn't even realize was inside her. She couldn't even give it any love before losing it.
While she has been maintaining a 'neutral stance' since Kanade apologized, Akane resented her sister.
No matter what Kanade did in the past, she has never gotten angry or held a grudge. But this time? This time it was because of Kanade's jealousy, because Kanade spouted those words to grandmother. If Kanade never said that, then Grandmother wouldn't have thought to investigate her. Grandmother wouldn't have known about her helping Sumire.
Kanade's petty jealousy leads to losing the life of an innocent child.