First off, the issue of sexuality doesn't bother me a bit. It's the really graphic stuff with lurid descriptions of "the act" that get to me. That's why turn the lights off! ;-)
Anyhow - I liked the relationship defined here between the boys. I'm not so sure that attitudes about homo/hetero/other-sexuality would be quite so overblown in the Wizard world as they are in ours. After all, Dumbledore was gay!
I have always viewed Scorpius and Albus as best friends, but I never considered this, even though I have read Harry/Draco slash before and enjoyed 'some' of it. As I said, it doesn't bother me if it's well done. This is.
I've helped raise 5 boys, none my biological ones, and I've always made sure that they understand - usually around the thralls of puberty when things get exciting for them - that I would support them even if they wanted to take a sheep (OK, Aberforth, a goat!) to the prom. I'm not too sure I agree with the attitude that Harry seems to have here, although I can certainly understand it being like that. Too often, in our world, this is exactly the case. Well done piece here, though. Tasteful, with a touching ending.