Wendi is the human version of Toby's dog mother: she's poor, she's scattered, she doesn't take good care of her puppy, she doesn't let him out to exercise, and she probably shouldn't have a dog in the first place.
Okay, technically, Wendi didn't go out and get the dog; it was given to her by her boyfriend. But she did ask for it. Couldn't she have asked for an iPad instead?
The dog, named Bear by Wendi, feels about as much sympathy for Wendi as he did for his original dog mother—which means he feels just about none. Instead, he wants to get far, far away from her. As Bear observes about her, "I could feel sadness at the edges of her feelings and wondered what it was all about. Perhaps she was bored all day, too" (26.38).
Bear also observes, "As far as I could see, life with Wendi had no purpose whatsoever" (26.34). Do you think Bear is maybe this close to saying that Wendi herself has no purpose? Why doesn't he try and help her find her purpose?
Perhaps he doesn't have enough time to help her, as she gives him to her mom Lisa and her stepdad Victor, who soon abandon Bear in the woods. It's a blessing in disguise, as Bear soon finds his way back to his favorite owner, Ethan. Wendi might never know that her purpose was to reunite boy and dog.