I saw this really interesting post by @slitheringghost and @artemisia-black, but as I am planning to stray a bit off topic, I thought it best to just paste it here and continue my rambles:
literally where in the world are people getting “sirius only cares about his friends / his chosen few and no one else”. this is fanon. there is nothing in canon to indicate this. canon sirius as an adult is nice to molly weasley and comforts her about percy despite their differences. of course, adult sirius is very different from teen sirius, but young sirius as an eleven year old moves over for lily at the sorting despite having just met her (and made fun of her!). and given his breaking away from his family, i think he’s very open to getting to know other people to hear different perspectives, especially muggleborns. sirius cares about people a lot and that is fundamental to his character. also, how could i forget - MADAME ROSMERTA!
The way he had tea on everyone in the cave showed he cared about more than just his inner circle (even if that was just observational).
I don't want this to come across as an attack on the wolfstar community, but I think the question of where in the world are people getting “sirius only cares about his friends / his chosen few and no one else” can be answered by those who want wolfstar to be canon. The fundamental premise of wolfstar is canon is that Sirius doesn't care about anyone other than Harry and Remus by the time we meet him in POA.
Take the famous: Remus Lupin/ Sirius Black Ship Manifesto:
According to J.K. Rowling, an animagus form is defined by the wizard or witch’s personality, and never is this more clear than in Sirius’s case. When the transformation is complete, he becomes a massive black dog and, like a dog, his defining point is his devotion to those he cares for, a devotion which comes coupled with both protectiveness and a certain narrowness of focus. But there are two sides to Sirius Black, for along with his endless stores of affection comes the tendency to dismiss those for whom he holds no real love, and outright hostility towards those he dislikes.
...
Additionally, they each form deep bonds with their own which sometimes transcends reason: Remus is one of three people Sirius actually listens to, and for Remus, thirteen years melts in a single look of understanding. (...) Furthermore, Sirius himself is a charismatic figure, and because he is so judgemental, his rejections so extreme, the acceptance he shows becomes all the more precious. (...) It's in the way Sirius will listen only to Remus, and the way, once reunited, Remus is free to be assertive in a way he never had been before.
All of this is incorrect and ignores things we see in canon: Sirius listens to almost everyone. Sirius listens to Ron and Hermione: "I think they've both got a point." Sirius listens to Dumbledore (even if he doesn't like it). He listens to Harry to the point of deciding not to kill Peter, after that being the only reason he broke out of Azkaban. Sirius even listens to Rita Skeeter insofar as he realises that, in-between all the nonsense, there are things of value. Second-hand, he listens to Winky when Harry relays what happened at the World Cup.
It's not really by chance I don't think. Peter might be the spy, but it's Sirius who acts like one: always listening to people, gathering intelligence. He spends the entirety of GOF behaving like a spy: living in a cave, sometimes moving in amongst the people in disguise to gather intelligence etc. No wonder people have no trouble believing Sirius is a double agent.
It's ironic that Sirius' two downfalls is him misreading people, when he's mostly displayed as someone who's really good at both listening and understanding most people, whether it be Barty Crouch Sr, Winky, Harry ("Nice try, Harry") or indeed Molly. Yet, he gets the wrong measure of Peter and Kreacher. Or maybe it's not that weird. When you can read people well, you're more likely to trust your judgement.
Of course, he listens to Remus in a heated argument, as long as Remus speaks reason. Remus canonically has limited influence over Sirius or James. He can make them feel guilty in choice moments, but he knows that it's contingent on him being right and tactical about it. He does not stand up to Sirius and James while they're bullying Snape. He is mindful about how he proceeds when he inserts himself in the argument between Molly and Sirius. He is not someone who Sirius listens to unconditionally.
Which is why I fundamentally disagree with this sentiment: "For Remus, Sirius’s unconditional loyalty is a godsend. Without fear of losing Sirius, Remus is freed to become a more self-confident and assertive person." -- Remus canonically fears losing his friends, as even the manifesto explains in JKR's own words: "Lupin's … a very nice man but he has a failing and his failing is that he does like to be liked and that's where he slips up because he has been disliked so often that he's always so pleased to have friends so he cuts them an awful lot of slack"
But the basis for a canon claim to a relationship with Sirius and Remus has to be that Sirius is only kind, and only listens, to those he truly loves. Or at least, this is one of the more common lines of reasoning I see. Which is a shame, because I think a relationship between the two where Remus recognises that his influence over Sirius is at best limited and that Sirius cares about many people and is willing to die for pretty much anyone as long as it is in the name of justice ("only innocent lives, Peter") is a much more interesting dynamic. And it does Sirius a whole deal greater credit.
Let's not get into the fact that even if Sirius only listened to three people, whether that is meant to refer to the Marauders or Harry, James and Remus (I really don't know because the Marauders ignore Harry and Harry, James and Remus ignores Peter who literally fools him), that still doesn't prove romantic undertones, unless you're also going to be advocating for SiriusxJames and SiriusxHarry and/or SiriusxPeter.
