In Chapter 5, is there evidence that Brent has never before had to take care of himself? Explain.
In Chapter 5, titled "Twinkle Twinkle Little Star," Brent realizes that he hasn't packed any long-sleeved shirts, nor has he remembered to pack shampoo. As a result, he's too cold, and his hair is stiff from being washed with regular soap. These details indicate that, if he'd ever gone on trips before, his parents had probably been the ones to help him pack, or at least to remind him to bring appropriate items for the weather and for his personal hygiene.
Also, when Brent arrives at the bus stop in San Diego, he nearly loses his backpack to a pair of thieves, not realizing quite quickly enough that one of the thieves was attempting to distract him while the other grabbed the bag. Brent's gullibility and willingness to allow a stranger into his personal space suggest that he has not been alone much in the real world outside his suburban community back home. But he learns from the experience and now knows that taking care of himself demands a higher level of vigilance, even from the strangers who inhabit the "anonymous community" to which he feels a strong new connection.
Other than these small indications that Brent has rarely, if ever, had to take care of himself before this trip, he does very well in new situations in this chapter. He picks up new skills, from recognizing constellations to trying the harmonica, and he learns that other people his age are actually interested in museums, that men can cook, that politics is actually an engaging topic of conversation. Brent even learns from his mistakes as he builds the whirligig. All these new ideas and experiences broaden Brent's mind in Chapter 5, helping him become a more self-sufficient (and interesting) person.