"Bloody hell, fuck you" muttered Regulus, as Sirius took yet another knight. Regulus was not having a good chess day. Most days, he could kick Sirius' ass at chess with his eyes closed, but today was not one of those days.
"Ahh yes, that's my favourite Slytherin, always so gracious in defeat" laughed Sirius.
"Hmm" grunted Regulus sharply.
Sirius paused. Although to most, this might have seemed like exactly the sort of cold, non-committal response you would expect from the youngest Black brother, Sirius knew him better than that.
"Reg what's going on?"
"Nothing."
"Well I didnt get a sarcastic insult, and also I'm winning, so there must be something wrong, and you can deny it if you want, but you can also tell me if you want"
Only brothers could be simultaneously that annoying and that supportive.
"I'm fine" hissed Regulus, shakily "it's just really loud in here, lots of people you know?"
Sirius did know. The common room, although lovely, could be horribly loud and bright at times, and did sometimes feel like a sensory overload hellscape, and the sheen of tears and bouncing leg Sirius could see in his brother were all too familiar from the mirror.
"You want to go somewhere else?" Asked Sirius softly. Regulus just nodded robotically.
---
"You know," Sirius remarked as he moved a pawn, now happily settled in the (much quieter) library
"You should really think about getting tested for autism, it made things so much easier for me once I was diagnosed"
Regulus tensed up a little,
"Yeah, maybe, I dunno" he muttered.
"Wait, do you not want to?" asked Sirius asked tentatively.
Regulus' fingers started twisting his hair a little faster, and a little tighter, as though he were trying to cut off the blood supply.
"I dont know okay." he snapped, Sirius reached to put his hand on Regulus' shaking leg, and Regulus flinched away, physical touch might be his love language, but there were still days when he thought he might explode if anybody touched him.
"Reg love, you do know its not a bad thing right? I mean if you get diagnosed it doesn't mean there's anything wrong with you, in fact it's-"
"Its not that okay it's just.. I mean I just.." the sheen of tears over his eyes was starting to turn into a pool, and flowed steadily over his lash line.
"I mean what if we're wrong" he whispered.
"What?" asked Sirius
"What if we're wrong?!" Regulus all but yelled.
"I mean that's fine too Reg, it's okay-"
"NO Sirius it's not! I have spent my whole life, my whole fucking life, thinking that I was fucked up, and broken, and weird, and just fucking beyond repair, and then someone tells me that maybe I'm not, maybe I was always meant to be this way, and I'm not the only one, and maybe I'm not so fucked up after all, but if we're wrong..."
Regulus let out a desperate sob.
"If we're wrong then that's like confirmation that I was right the first time. That I actually am just broken. And would you even be surprised, given mother and father? I can't face that. I'd rather not know at all than know that I really am just pathetic and stupid and weird and, and"
And Regulus broke off into gasping sobs.
"Reggie. You are not any of those things okay? There is nothing wrong with you. I can promise you that, and maybe mother and father did fuck you up a bit, they sure did for me, but that does not mean you are broken, okay?"
Jesus Christ, sometimes looking at Reggie was like looking in the mirror.
"Sirius?"
"Yes?"
And Regulus shuffled towards Sirius and burrowed into his arms, and not a word was spoken, they just held each other, just like they had since they were born. Just like they would until the day they died.
Just chess and love, for the rest of their days.