Is there a specific reason Nero and Brutus aren’t especially close/friends even though they have a similar age gap Brutus and Lyme(best friends)do?
OK so -- they are friends! I just haven't have room to write it much
Nero / Callista / Brutus is a great dynamic that I have only ever hinted at the edges of. Both Nero & Calli adopted Brutus when he was a baby victor, which is why he's one of the chief babysitters of her cats even though he grouses and says he hates them (like all those videos of dads-who-hate-the-pet lmao). Brutus ALSO had a wicked crush on Calli and got put down pretty quickly but she learned from Nero to be a bit less, ah, shot through the heart about it.
Brutus & Nero have a very "he's one of my best friends, we still never talk sometimes" relationship where they sit and maybe have a drink and build something with their hands, and it helps Brutus process stuff when he doesn't want to talk about it (this is often). He's also often the victim of Nero's sense of humour (I have another ask sitting about this lol SORRY) but there's a random thing in a fic somewhere about Brutus having to build Nero a cedar chest after losing a bet with him (Brutus is allergic to cedar, not majorly but it makes him sneeze) and I feel like that's a common theme. As in, they have a long-running history of stupid bets with stupid stakes for no reason.
Brutus is one of the ones who knows about Nero's deal and takes on several of his sponsors when he can. They do NOT talk about this.
(Brutus and Lyme specifically was engineered by several parties as soon as it became clear Lyme & Emory would not work (from BOTH sides to be fair, this isn't just "Lyme would be mean"). They probably would not have on their own. Cross-generation ("generation" lol but you know what I mean) friendships DO happen, Calli and Adessa are famous stitch-and-bitchers, but they had common ground from the start. Brutus and Lyme needed a bit of finagling.)
Brutus / Calli / Nero really is just a tragedy of POV i think, in Fixed to a Star he says Brutus and Lyme aren't friends because they don't act naturally in front of him when he's fresh out. Although I do think that they were a stronger unit when Brutus was younger and once he and Lyme really took off as friends Nero & Calli released him back into the wild with a sense of accomplishment. They'll still hang out (and torment) him sometimes, but he has a bigger emotional world now.
(The sad thing is they probably spend more time together on the Capitol circuit but I don't write that as much for obvious reasons)
i would say i'll try to keep this in mind for something but "fic where brutus and nero build a chair in silence" is more of a visual medium type thing and comics are not my specialty