Describe the use of irony in "Charles," whats irony in this story

I think it would be don't gullible enough to believe everything your child tells you. Jackson loved hearing the stories her own son would tell about the class bad boy, Charles. In fact, she couldn't wait for Laurie to get home from school so she could hear them. All the while Laurie was misbehaving at home. In the end, she learned there was no Charles and that Laurie had been pulling the school pranks he blamed on Charles.