It was really depressing, but it was such a personal story you couldn't help but like it.
It's funny you mention the brothers, the youngest one was a girl, but for the life of me I couldn't figure out if it was a boy or girl until near the end he finally referred to her once as his sister.
It was frustrating to watch as he tried to care for his sister, but slowly let her die out of ignorance.
I'm not sure what you meant by open, as both main characters die during the course of the film, although they sort of live on as ghosts. (or something, it was difficult to discern if it was their ghosts reliving the tragedy or just his memory during the last moments of his life.)
Either way, it was still a good movie, just very very depressing.