What I remember: future fic with Kurt and Blaine in NYC, they have 2 (?) kids, and Kurt performs on Broadway. I think Blaine might be a teacher of some kind. Kurt falls ill-- passes out and has rapid heartbeat and can't catch his breath--they're worried it might be a heart attack like his father, but it turns out to be something bacterial or viral. He was hospitalized for a awhile, and at one point might have been in a coma. I remember a huge part of it was Kurt's getting back to normal an trying to get Blaine to not treat him like he's going to break again, and have sex with Kurt again as normal. They have a huge fight at one point and Kurt storms out only to get down the block before running out of steam? I hope this rings a bell with someone, because my advance Googling has failed me spectacularly.