Even though the first Robin, now Nightwing, is one of the kindest members of the Bat-Family, it's hard for anyone to get along with Jason Todd, AKA Red Hood. The first two Robins have a rocky history, especially since Jason was the first to replace Dick Grayson as Batman's ward. However, DC revealed that, upon meeting each other, Dick's initial thoughts on Jason were exponentially insulting to future moments in Red Hood's character history.
Once Batman starts to miss Dick after he became Nightwing, Bruce chooses to take in Jason Todd, whom he catches him trying to steal tires from the Batmobile. Despite the popular stories Jason is in, his most iconic remains Jim Aparo and Jim Starlin's A Death in the Family—the story that has Joker famously kill the second Robin with a crowbar. What makes the tale so historic comes from DC's poll that prompted fans to kill or save the Boy Wonder. Fans ultimately voted for the Joker to kill Robin, most likely because it was an unpredictable choice. Still, even after Jason's resurrection in Batman: Under the Hood, he arguably remains one of the least favorite Robins, both within and outside of the fictional universe.
Scott Beatty, Chuck Dixon, and Scott McDaniel's Nightwing: Year One (collecting Nightwing #101-106) tells how Dick Grayson got his "disco" Nightwing costume and his first encounter with Jason Todd. After meeting Bruce's new ward, Dick thinks to himself as if he were speaking to Batman: "A sneaky, mean little punk. Maybe you hired him before the Joker could." While it seems like a mere jealous thought, if Jason knew Dick thought this of him in modern comics, it would absolutely crush him. Jason has one of the worst traumatic experiences with Joker in comics history, probably next to Barbara Gordon's paralyzing injury. Jason also admires Dick for being a reliable role model to follow as the oldest Robin. The fact that Dick was reminded of Joker when first meeting Jason as a child is such a devastating blow.
Additionally, according to Batman: Three Jokers, by Geoff Johns and Jason Fabok, Jason Todd's biggest fear is turning into Joker. At one of the most suspenseful moments in Three Jokers, Jason has his tormentor at gunpoint while Batgirl urges Jason not to kill Joker in cold blood. The Joker allegedly recites some of Jason's pleas in Death of the Family: "If you let me live... I'll do anything you say. I'll be your Robin." Obviously, Dick never knew the modern context of Joker torturing Jason or suggesting he would be a better sidekick for the Clown Prince of Crime. However, if Jason knew Dick's first thought that Batman adopted Jason "before the Joker could," it would definitely pour salt on the wound.
It can be aggravating to get along with Jason's dark and unforgiving personality, especially for Nightwing. Nevertheless, it's evident that he needs all the support from his Bat-Family. Heroes like Barbara Gordon and Dick Grayson can be there for the broken Robin in moments even Batman can't understand. As a fellow former Robin, Nightwing can give Jason Todd the kind of support he can only get from those who know what it's like to be in Batman's shadow, making the Bat-Family the best resource for DC's bat-related vigilantes.