Gah, the ending to this story. It's like the scrape of nails over a blackboard, the idea that this is a circular thing between them and not anywhere near over.
You take so much away from Neville, show us his anguish so very clearly, and yet Snape also gives him one of the things he needs at the end - along with a promise of something.
Such a brilliant and painful story, perhaps even more painful because of the tendril of hope at the end.