The whisky burns his throat, even the morning after. That's one thing which has never changed, though so much else has. It's not enough to stop him drinking it, especially not on late nights with the house empty except for that accursed house-elf. (When Remus is here, he doesn't feel the temptation, doesn't have to deal with that aching emptiness in his chest, and for a little while he feels reasonably human again.)
So much of his memory of Before has been eroded thanks to Azkaban, consumed by the Dementors. Some memories still stand out as sharp and clear as lightning – childhood adventures with Regulus, the Sorting, the moment Remus confirmed his lycanthropy, his first successful transformation, telling Snape where to press the knot on the Whomping Willow, the crowning moment towards the end of seventh year when he and Remus kissed for the first time (after James and Lily talked sense into both of them), the wedding, baby Harry. There are great swathes of time of blank impressions filled only with Remus' own re-collections.
And then there is That Night – a fleeting torrent of memories – the dawning comprehension of Peter's betrayal, the house destroyed, James and Lily lying dead and little Harry – scarred and crying – pressed to his chest as he tried to soothe him through his own tears, watching Hagrid fly off on the motorcycle with Harry, the all-consuming grief which drove him on until he found Peter, echoing laughter after the explosion melting into the pressing walls and aching cold and desolation. Desolation which was all that he knew for twelve years.
He could have escaped at any time, could have slipped through the bars and swum home. But he'd deserved that prison, he'd sold them out by allowing Peter to be Secret Keeper. He should have done the job himself, would have kept the secret until death and instead he'd thought he was being clever. Of course he deserved prison, but not for the murder that everyone thought.
In the morning, Remus comes back and finds Sirius slumped over at the kitchen table, empty bottle of Firewhisky sitting by his hand. His head is pillowed on his arms and the long hair hides his face from view. Remus is loath to wake him, loath to bring him back to the memories which drive him to this as often as not. There's a part of him which blames Azkaban and the Ministry for this, a part which blames Voldemort for starting it all, and no small part, though hidden away it is, which blames Peter for selling out the Potters. Mostly, though, he blames himself for not looking at the evidence, for believing them when they told him that Sirius was a traitorous murderer. He should have fought harder, should have defended him, but he didn't and this is what they've come to.
There's nothing else that Remus can do, so he does what he can – disposes of the whisky bottle and pulls up a chair, wrapping his arms around Sirius so that when he wakes he'll know that he isn't alone.
And maybe today will be one of his good days.