Sam's little sister, Haley, would probably get along super great with Bridin. With the exception of the whole being half werewolf, half fairy thing, they've got a lot in common—both are serious type A personalities, overachievers, and have older brothers who tend to be overprotective. "[Haley] was one of those people who excelled at everything she attempted without actually trying to," Sam describes. "Since she was my little sister, that made me proud. A little envious, but mostly proud" (11.11). Go, Haley, go.
Haley's not a character that gets a lot of action in the storyline, but she does serve to add dimension to Sam's past and how it's shaped him. It's obvious that while Sam is proud of her, it also can't have been easy to have her as a sister. After all, she has some big shoes, even if she's younger.
When his mother comes clean to Sam about his necromancy genes, he finds his past explains why she seemed to be more distant with him than Haley. "There was never any hesitation with Haley," he observes. "I always thought it was because I reminded you of Kevin" (14.27). While Sam loves his sister, it's clear that she's a source of tension in his life, not just because she's awesome, but also when it comes to his relationship with his mother.