Luck and Cue!! I love those guys!
I'll start with what they do! Cue handles the more professional stuff, and inner workings of the family, while Luck is more like an ambassador, checking in on local business they're "partnered" with, befriending even those they're not, doing his best to make Aster a name with predominantly positive association for most.
Honestly not too dissimilar to how the Mafiafell brothers' work dynamic functions, too, except Cue handles the more official publicity type of stuff, and Luck usually handles the, uh. "Sensitive matters".
As for their relationship, it's still pretty good, if maybe a bit more distant than classic US. They do still look out for each other, that loyalty is absolutely still there, but things are just...a little stilted between them. Almost not as close as brothers, sort of more like very good old friends, but not entirely. A little hard to explain, but they do know each other very well, even with the rift that'd grown after having the torch passed to them.
Luck is a bit of a brat and loves to do things for the sole purpose of annoying Cue, however he learned very early on Cue wouldn't bail him out if he really wanted to teach him a lesson and is careful about taking things "too far".
Cue, while caring deeply for his brother, feels like entertaining his more rebellious nature is just coddling or humoring him, and he doesn't want to encourage that, so he can be a bit hard on him, but whose to say that isn't deserved?
They tend to step on each others toes, and neither really wanted to live this kind of life and sort of had it forced on them unexpectedly, but they cope with that in entirely different ways. Though it's still significantly better for both than it'd be if either had to do it alone, that's for sure