Oh God.. I don't think I have words adequate enough to describe how deeply this moved me. From about 5K in, I had a lump in my throat and it didn't go away the entire time i was reading. I feel like I've been taken through the whole of Harry's life, and Snape's life and I rejoiced when Harry joined him in his portrait.
So many wonderfully amusing little lines, so much fantastic, so very Snape lines and snark. so much angst and Harry with Draco, I felt Snape's pain and Harry's mortification.
*swallows around the lump*
His portrait was a replica of my Slytherin bedroom, dominated by an enormous bed quite big enough for two men. Generally, I wasn't the sort of man to leap to conclusions, but I would say he had an agenda.
This just made me burst out laughing and then dissolve into tears.
Thank you, so very much, for what I suspect must have been the pouring of your heart into writing this.