Al took in Severus' offer of the memory in the way he always viewed memories: the most precious gift one could share with another human being.
He took in Severus' clipped words and his sister's answers and experienced Severus' searching probe of Legilimency into Lily's mind as if he himself was casting the spell. He absorbed the flashes of his sister's thoughts, compartmentalized in beribboned boxes. How curious. Al's own compartments were the dusty, dark drawers of a well-organized library archive which sorted themselves in oh-so-many ways, except when their contents rose up spinning like a cyclone, but not anymore, not since Al learned to use other thoughts to keep the explosive ones in check.
'...Except... Al. Albus. Is he well? Tell him that I asked.'
'He is well.'
Al latched onto the images and the words and the sounds and the emotions offered to him so freely and absorbed them, remembering every moment, every impression.
The memory was especially precious now, that it had no original owner. So it was up to Al to keep it alive.
If he did not, no one else would.
It was only afterwards, that the odd thought struck Al, a revelation never discovered before in these three-hundred-and-fifty-five days that he knew Severus.
You are... different around others, than when you are with me.