Oddly for the book like this, the time the character spends in the real world is far more unbelievable than the time he spends in the fantasy world. His evil parents are too cartoonish to be plausible. The world simply doesn’t work the way the author portrays.
Maybe it’s due to my listening while doing household tasks, but I found the plot line pretty confusing, with characters doing things for inexplicable reasons.
As for the narration, others are correct in that the main character’s voice is very annoying; the narrator probably felt he had no choice, since the book describes the voice as deep and gravelly, but that sort of voice is ridiculous as the character tries to engage in light, witty banter. The narrator should have used his judgment to substitute a voice more pleasing to the ear.