I am not sure how to accurately convey just how much I love this. The scene you've set is just brilliant but in the end it comes down to this:

It takes all of his remaining strength, but Harry reaches out and grabs Snape's wrist before he can retreat.

"You're alive," Harry says. He probably should find words more profound, but they are all he can manage.

Snape carefully withdraws from Harry's grip and sets Harry's hand down on his stomach. His touch lingers for a moment.

"And so are you."

*clutches chest* Love, love, LOVE that. Marvelous work, bb.