Oh dear. This is insanely long, so please bear with me and indulge my need to flail.
This is a difficult story to leave feedback on, because it's so astonishingly right and perfect: every word, every part deserves praise, and I feel as if I have too much to say and that the need to say it all leaves me tongue-tied. It's so exquisitely balanced and inflected, with a cumulative effect far greater than one would expect from fewer than 6000 words. The distilled prose scatters passing hints in plain sight, deliciously subtle without sacrificing clarity (I say 'delicious' because the subtlety and underplayed emotion are handled with such skill that it makes me squirm with pleasure.) The tenor of mind is pure Aberforth, conjuring the limits of his world but not of his knowledge; there's also a narrative distance from him, detachment of a sort, that allows a larger perspective on each nuance of character and each glancing allusion to canon without manipulating the text or spoonfeeding the reader. It's all implicit, and it repays the act of reading into it, of allowing all those hints to build in power without ever breaking the suspense or forcing the characters into unseemly confession.
Also, I adore outsider POVs, and as a sharp and unsentimental portrait of young Snape, this gives that impression of fresh eyes and unexpected angles, informed by Aberforth's familiarity with his brother's methods, if not his exact intentions. His pragmatic hands-off policy regarding the boy's guilt and fate, not to mention the separate question of Albus' responsibility and offstage judgment, makes the sexual intimacy more poignant, an apparently forthright physical release complicated by literally everything else that brings them together. But at least it comes (not a pun!) without a price tag. I also love the contrast with canon, in which we get a boy's-eye view of an adult Snape, whereas here we have a nonagenarian's view of a Snape just past boyhood, incredibly young and self-absorbed but dragging behind him the consequences of horrific mistakes most people can't even fathom. Aberforth, of course, can. His world-weariness and his acceptance of damage as an inescapable part of life make him the perfect custodian of Snape's struggle to survive this year. He's a farmer who practices co-existence; a naturalist trained to observe but not rescue, except insofar as his mere presence gives the boy sustenance, and his understanding, however little Snape himself understands as yet, creates a more compassionate environment than whatever the boy is getting at Hogwarts.
I'm going to single out some of my favorite moments, which will be at the expense of all my other favorite moments, because there's nothing here that doesn't in some way fascinate, tease, enlighten, impress, startle, and take my breath away. Just so you know.
Didn’t look like much. Obviously valuable nonetheless. Most likely dangerous. Just like that, Aberforth has me in his pocket. This is a wonderfully astute summary, delivered with brevity and sharpness. It also delights me that he identifies Snape through his family resemblance to the sheep-breeding Princes.
The boy hadn't been trusted with silver. That was Aberforth's first clue. So many small, pointed hints reflected here: the economy with which you show Snape's ambiguous status, Albus' caution in removing temptation from his path, Snape's poverty and perhaps avarice treated as a given, and the fact that Aberforth isn't in the know but is obviously in the habit of assessing his brother's projects even as he grudgingly acquiesces.
There was a certain expression shared by those who had never expected to find themselves here, in a room like this one, but this was the first time Aberforth had seen it on the face of somebody with boots that shabby. Ah, this squeezes my heart a little. It reminds me that Snape sold his teenage soul in order to escape a childhood full of shabby boots and cheerless rooms, and now he's staring at an endless vista of servitude and emptiness filled with iterations of shabby boots and rundown beds. I love that Aberforth leaves him to it without a word, incurious and not presuming to jolly him out of it. And that he immediately seeks and finds confirmation of a bad omen.