4. Shiori is all along not only protecting Hinako from other beings but conning her into preserving her life until Hinako comes again to cherish her life.
chapter1, page 14
That quote makes it save to say that her parents saved her and told her that at least she has to life.
You can't just kill yourself if others died for you.
It's too soon to try to predict endings. I look forward to see how the mind of a suicidal person works in future chapters, that's a concept I rarely see at all.