They're really not. Most of the protagonists in his books are working class, some of them are impoverished. They aren't figures of fun, and the books have a real undercurrent of sadness in them. The boy in the dress is about a cross-dressing teenager.
Yeah I know fuck all about these books and that, but upon looking up 'Billionaire Boy' and finding that it seems one of the main jokes in it is that Mr.Raj the Pakistani/Indian/youknowsomeAsianladwhocouldn'tpossiblydoanythingbutrunacornershoporakebabshop shopkeeper has heard of £50 notes but never seen one before, it did seem like maybe there was a bit of a problem there.