Bud's experiences in Hooverville appear in chapter 8 of Bud, Not Buddy. He and Bugs meet a variety of interesting characters in Hooverville, and many of them show genuine care and concern for the two boys, but I do not believe any of those people would qualify as family for Bud.
One way to answer this question might be to say that while in Hooverville, Bud does have a family; however, he just isn't with them. He has a living blood relative in Calloway, but Bud doesn't know this and is not with Calloway in Hooverville. You might also be able to make a case that Bugs is Bud's family. The two boys are emotionally close due to shared experiences on the road and in the orphanage, but I would say that the two boys are friends rather than stretching the definition of what a family member is.
The people that Bud meets in Hooverville do show a genuine care and concern for Bud, but there isn't a sense of familial love about them. They care for Bud because they are in similar down-and-out circumstances. Additionally, I don't believe Bud stays in Hooverville long enough for anybody there to be considered family.
Personally, I never got the feeling that there was a sense of love in Hooverville, and that missing element is why I would say that Bud does not have a family there. This is why I would support the idea that Bud has a family in Lefty Lewis and that family. Bud spends nearly the same amount of time with Lewis's family as he did in Hooverville and the Amos household; however, Lewis's family treats Bud as one of their own. They give him a home-cooked meal. They give him a warm bed to sleep in. They give him clothes. They do all of those things without asking for anything in return. Bud has a family in that household.