Regulus was allowed to have friends over. Sirius's friends were not welcome. So Sirius only thought it fair to another. That is why he walked into his brother's room unannounced. However, what he found was unexpected. He made a dignified noise (not dissimilar to the squawk of a dying bird) at his brother back against the wall with his hands in another boy's hair, his lips moving against that of the other boy. In a panic, the two jumped apart.
“I… uhh lost time… track, track of time... Must be going.” The ‘friend’ said in a panic before rushing out of the room without closing the door and disappearing by way of the flew before Regulus could unfreeze and attempt to figure out what to say.
“I...uh.” Regulus started then trailed off.
Sirius glared at him raising a finger to his mouth, and walked backward silently keeping an eye on Regulus he closed the door and cast his best silencing charm.
“What were you thinking!” Sirius even with the charm, was careful not to be too loud. “Mom could have walked in at any second. How could you be so stupid, your not supposed to be the reckless one? You didn't even lock the door or put up an intruder charm. You would be lucky to get the boot and not the bucket. I am not in the mood to go to your funeral.”
Their relationship had been strained for years, Regulus had thought this would be the last straw, the ‘how dare you judge me when your worse’ or even Sirius’ chance to regain his family's respect, admit he was bad but the better of two evils obviously. He knew how to respond to that, how to throw fire back, he did not know what to say about genuine concern.
Sirius watched as the first tear rolled down Regulus' face. He saw the weird smile flicker in the pain. They hadn’t so much as touched in years, except a few punches here or there, but in that moment for once he knew what to do, how to be an older brother.
“Regulus, come here.” He motioned with his hands, he let down his guard letting his eyes show the fear and the compassion, and maybe just a glimpse of understanding, of empathy. Regulus carefully stepped forwards and was wrapped in a tight hug. Regulus tensed at first, then collapsed into Sirius and started sobbing.
“Regulus, it's ok you're ok, it was only me, I’m not going to hurt you”
He was struggling to speak through sobs and let out a lot of unintelligible gibberish before he calmed down enough to get out a full idea, then his words flowed out too quickly for Sirius to respond. “I don know what to say, I know it's gross and wrong but it doesn’t feel that way to me, not when I’m with him. You really aren’t going to tell her? You should, you should hate me, you should be disgusted by me.”
Sirius sat them on the bed and moved back just a little to look at Regulus. one arm to cast some spells on the door.
“It’s not wrong, Reg. I don’t think the same way as them and you don’t have to either. You may think something is wrong with you now, but sometimes you just have to accept that all the little ways people are different aren’t flaws, even when it’s yourself, especially when it’s yourself. I know it’s been rough for us, but you're my brother, if I don’t hate you you shouldn’t have to hate yourself.” Sirus did still hate himself a little somewhere deep inside, partially for how sappy and self-help book-like he sounded and just then and sometimes because he couldn’t shake what he had heard his whole life. That fact it combined with the slight fear that Reg might be forced to use the truth against him one day, that lack of trust their family had ruined so deeply in them from childhood, that was keeping him hesitant over his words, unable to share
“It’s just so lonely, he’s the only person like me I know and I can’t even really talk to him about it, he just wants to make out and leave, he doesn’t even like to talk.”
This was the now or never moment, this conversation he had to.
“People like us are everywhere you just have to know where and how to look, they form their own families, and they genuinely love each other. It’s not all shag and goes, there is real love out there.
“Like us?” he stared
“Like us.” He met his gaze
“You have people who know? Sirius and you called me stupid, what if they said something.”
“Some of them needed a little time to adjust, but I found community, the important ones came around in the end and care enough to keep me safe. My friends, my boyfriend, Uncle Alphard, McGonigal caught me with a shirtless lad once so I think she knows…”
“You have a boyfriend? Wait, is Alphard I always kinda thought something was up.” He has calmed but still had puffy eyes and flushed cheeks.
“Yes I do, and how did you not know that the whole family was the only reason he didn’t get officially disowned is that he is popular with a few high-ranking people in the ministry and could topple the family?”
“Do you really like that jerk boy?”
“He’s not bad he’s scared. I like him and he likes me, E=but every time I make a move towards a real relationship he freaks out.”
“Sounds like how I used to be before I felt I belonged.” Sirius paused. “You can still make friends who don’t think like our parents, take him with you or don’t. It's not too late. Never too late. Why don’t you tag along with me to a couple of the parties Slytherins don’t go to? Or at Hogsmeade sometime next year. Meet new people and show them you're not actually all that scary.”
“Sirius, you know I can’t. They hate me.”
“Maybe now, but that can be changed. Things are bad. I don’t know how much longer I am going to be here, but I don’t want to lose you if I get kicked out, okay.”
“I’ll think about coming. I should tidy myself up before dinner.”
Sirius got up to leave. “Regulus?”
“Yes”
“Take care of yourself for me”
“You too”
They nodded in understanding. Then Sirius closed the door. Both of their head reeled they parted. 4 days later the big fight happened, Sirus will say he ran away, and Walburga will say she kicked him out. Regulus will wall himself up in his room alone for the rest of the summer.