Charlie is generally a good natured kid, but he makes predictable mistakes, and wants to impress his friends in a very typical 5th grade way. He is more self centered than his little sister (who gets by with cuteness) or his older brother (who understands how difficult things are for the parents), but he is not mean spirited about it. He just doesn't understand. It's encouraging to see that his parents understand this and try to help him grow as a person and learn to be empathetic to others.
This sixth book in the series covers a more serious issue than the other books, but pulls it off in a believable way. I especially enjoyed that Charlie's parents told him age appropriate details about what it meant for the father to be out of work. Matt is becoming my favorite, though-- can we see a slightly older set of books about him?