Whoa. This is amazing writing. You hooked me from the opening sequence.
This pairing just makes so damn much sense! Of all the people in the world who most know what Albus was like, and who could most sympathize with Snape, of course it's Aberforth. It's so obvious yet so brilliant.
Your Aberforth's voice is amazing. Absolutely perfect. I LOVE the way we get to see younger Severus through his eyes -- and that he never stops seeing Severus as a 'lad'. It's just so very like Aberforth that he would find Severus peculiar and fascinating -- or perhaps, fascinating for his peculiarity -- I think.