Such an interesting story! I really liked your Harry - bumbling, brash, and confused about life. I wanted him to figure out what he had done wrong and why he needed Roger, but I found myself satisfied with the ending. I also liked how Harry didn't realize it was Snape until he was literally beaten over the head with all the hints. I love your Snape as well - he has made a life for himself after the war and he's not apologetic about anything. I like that he only sells the potion once a month to the highest bidder, and I don't even mind that he has "boys".
While Lily got the happy life, the ending made me feel like neither Harry, Severus nor Ginny did. They're content in their lives, but they are not as happy as they could be. A lovely story. Well done.