Dave Wade, boy genius, is a kid who attends Jackson High with Mclean—even though he could have graduated years ago because he's really smart. But he wants to go to high school, work part-time at a café, and hang out with his friends just like any other teenager:
"He wanted to be normal," Riley said quietly, picking out another pretzel. Then, glancing at me, she explained, "Dave had never been in public school. He was actually going to go to college early, because he's so smart and got moved up so much. But then he decided he wanted to, you know, live like a regular teenager." (3.106)
Unfortunately for Dave though, these changes don't go over so well with his parents, who expect him to just maintain his geeky genius persona. Importantly, Dave gets what Mclean's trying to do in reinventing herself—after all, he's going through a version of the same thing. It's not easy growing up.
Maybe it's a cliché, but Dave Wade also happens to be the cute boy next door for Mclean. He lives right next to her and that's how she gets to know him so well—she first meets him when she finds him sleeping on her porch:
I was actually feeling good about things, basketball reminds aside, at least until I stepped out onto the back porch and found someone stretched out there on a stack of patio furniture cushions. (1.45)
After this weird and jarring introduction, Mclean starts to like having Dave so close at hand. For a girl who's so often home alone, it's nice to know that someone is right there to hang out with her—or watch out for her. Slowly, they get closer to each other, sharing secrets and hanging out whenever they can.
In fact, these two get so close that Dave is the person that Mclean calls on when she's freaking out at the Poseidon after running away from her mom's beach house:
But what about warts and all? I thought, thinking of that black ring on Dave's wrist. I looked down at my own wrist, the old Gert I'd tied there as I drove away from my mom's We each had circles now on our wrists, totally different and yet equally important. I knew my faults were many, my secrets even more. But I didn't want to be alone. Not at 2:00 a.m., and not now. (15.8)
Dave is the kind of friend that Mclean hasn't had in a long time—maybe never—and by just being there for her, she realizes that she can count on him. In fact, it's his consistency and dependability that make her shed her emotional armor and enter willingly into a relationship with him by the end. He understands her struggle to be herself, gently encourages her to live her truth, and greets her with open arms each time she does—in other words, he's one good dude.