We meet Donnie from the West Side Rollerz again. Apparently, even after five years, he still misses Lin and mourns her death. He even has a Voxel, Lin's preferred type of car with "in memorial" written on it. Seeing what Boss does to him, even if not as horrible as things they do, still makes you feel somewhat like a bastard.
The Boss visits Gat in the hospital after he got impaled with a katana and shows genuine anger throughout the Ronin missions after what happened. Given the character it's quite touching.
Gat: "So, the bastard's dead?"
Boss: "I cut him up myself. How are you feeling?"
Gat: "She's dead. You really gotta ask? Funeral?"
Boss: "We're waiting for you. How are you holding up?"
Gat: "Doc says I'll be up to murdering in a couple of days." Boss chuckles at this. "Well, he didn't say murderin', but you get the idea."
The opening cutscene to one of the earlier Brotherhood missions; Carlos has barely been living up to the Boss's expectations from their lieutenants, but the Boss nonetheless expresses their confidence in him, giving off a parental vibe rarely seen elsewhere in the game. Sadly, this makes what Jessica forces him through in the next mission all the more heartbreaking.
In the penultimate mission of the Brotherhood arc, one of the Saints soldiers can be heard shouting "THIS ONE'S FOR CARLOS!".