You're totally skipping over the letter she sends to break things off though.Munchenhausen wrote:Well, the believability of that would probably go as far as how you believe Iwanako's personality would be.
If you view it from her perspective, all she sees is that;
-She asks her crush out and his body suddenly shuts down in a visibly painful fashion
-She then finds out why it happened, he had a weak heart and she caused the infarction
-If she were to check on him a few months down the line, she'd find he either died (á la Kenji route) or has found love with someone else. Someone else who is also disabled, giving them both a strong link and bond
I'd say that was believable. It's not exactly unicorns and leprechauns
Then again, you're also skipping over all the times she went to see Hisao at the hospital, either because of her feelings for him or out of guilt, until Hisao's distant attitude drive her away.
Reqtified edition:
-She asks her crush out and his body suddenly shuts down in a visibly painful fashion
-She then finds out why it happened, he had a weak heart and she caused the infarction
-She continues to see him regularly and is the last of Hisao's friends, classmates and other hellspawn to do so
-Each visit Hisao is distant at best, and a cocktail of depression, fear and self-pity at worst.
-She could reasonably believe that Hisao also blames her for his heart condition
-She stops visiting (insert headcanon for reason here, though I'm sure mine is obvious at this point), but Hisao is still on her mind
-She finds out from Hisao's parents that he's transferred to a school for the disabled
-Guiltguiltguiltguiltguiltguilt with a side of depression
-The only closure she gets is in the form of a letter she sends Hisao, one that feasibly she didn't think to write herself, but was more likely urged to by someone else. the letter either gets no response or just a generic one that doesn't convey any feelings one way or another that he might have for her.
-If she were to check in with him later, she would find either he'd died, or he'd found love with someone else.