My Ds is 4 and enjoys being read chapter books. Has handled Enid Blyton's wishing chair and Faraway Tree series, Roald Dahl's Charlie and the Chocolate Factory and BFG fine although didn't like James and the Giant Peach (parents dying and bring sent to live with aunts). Likes Thomas books and Mr men etc. Also enjoyed Ferno from the Beast Quest series.
Would he like Christmasaurus or is he too young really?