I've mentioned a few times that Raf doesn't have a very fond opinion of Margie's parents [even...or maybe especially...after meeting them and seeing first-hand how they regard her and her passions, and choices, and accomplishments, etc], and he can't really connect with her older sister genuinely, because she's just...incapable of being normal about him, apparently.
But Raf gets along really, really well with Margie's younger brother, Benji. Benji's just a chill autistic guy who lives with the parents, smokes weed and plays video games when he doesn't have work. He's never really had to grow up and doesn't want to--but is a hard worker despite this. So long as you tell him what to do, he'll just do it without complaining--even if the task is insane. And he'll do a good job of it. He and Raf have this in common lmao (though Raf has his own initiatives/goals that he'll prioritise and is a lot more proactive--whereas Benji very much needs to be put in front of a task or have a goal dictated to him by someone else, as he won't take that initiative himself.)
Like Margie, Benji sees Raf as Just A Guy... and, like Margie, suffers a lot of second hand embarassment over the weird fixation/intense vibes their older sister, Liza, presents in her behavior towards Raf. Benji's room doubles as a place for Raf to hide when he needs some space--because Benji's energy doesn't sap the life out of him the way the rest of Margie's family does. They'll just hit a bong, sit back, listen to Iron Maiden or Judas Priest or w/e on Benji's sweet stereo system and Raf is chill to just watch Benji play whatever game he's got going on the playstation.
Thanks to this, Raf gets to know Benji better than he gets to know any other member of Margie's family, and they get talking about a lot of different things.
One of the conversations that sticks with him, I think, is one where Benji explains that he and Margie always swore off the whole "growing up" thing and agreed they'd always act like kids together without letting the world turn them into bitter, boring, joyless adults. As kids, they attribute "growing up" with all the things that made their older sister and parents kinda unfun and difficult to relate to.
When Margie was kicked out of the house and made to live on her own, Benji was genuinely concerned that the world was just gonna beat all the fun and joy out of her, and that she'd come back home one day as a dull, boring, joyless adult that he barely recognized. And he thanks Raf for finding her out there and giving her a place where she doesn't have to be anything other than Margie.
Usually Raf would argue that Margie has grown up...quite significantly--even just during the time he's known her. But he recognizes that this isn't what Benji means when he talks about "growing up" and "adulthood". Benji's definition of 'being an adult' is more akin to Raf's experience with adulthood; poisoned by pessimism, burnout, characterized by passionless incurioisity and bogged down by an oppressive, unyeilding self-loathing and fatigue. All due to the fruitless endeavor of trying to fullfill an impossible role imposed upon him by the uncaring population of his environment.
In honesty, the very first thing he noticed about Margie--before he had even heard her play music--was a certain je ne sais quoi, a joyful whimsy, youthful gentleness, whatever the hell you want to call it. It's what spurred him to reach out to her in the train station, very first time they met.
It was hard to imagine Margie without it. In truth, once Raf had sensed it, he didn't want to let it go. It was a subconscious thing, he didn't understand what he was dealing with at the time. But he'd have never agreed to go for coffee nor to meet with her again--if not for that precious sense of raw joy and wonder that she emitted so effortlessly. It was an endangered animal to him. And ever since meeting her, his life has become centered around preserving and nourishing it in her--and recapturing it within himself.
He has no way of knowing if Margie could have ever lost it, regardless of whether he showed up in her life or not. He errs towards the belief that she'd have always retained it--it's just too much a core part of her personality to bend to the environment like that. But he's really happy to have the luck--and the means--to foster and feed that part of her. Benji will never be without his fun-loving, joyful dorky sister. Raf hopes the same is true for himself, as well.
