The irony of sudden illness
The family says the story itself began with an unfortunate fate none of them expected. One minute, they were a happy family, and then, after their three year old became sick. It wasn't like cancer, which is slow and progressive. It was appendicitis, so things went from bad to extremely bad in only a matter of days. This is ironic because it is simply impossible to truly understand why illness should bring someone toward death so quickly and randomly, without notice. For the parents, the anguish of such sudden terror, followed by the relief of his resuscitation, helps set the stage for Colton's confession.
The irony of Colton's real-life medical miracle
Anything can be made overly-religious, so how can we distinguish the family's personal opinions about God from the reality of the situation? By remembering that Colton's real life story is truly remarkable. Whether the reader believes in God or not, the story about Colton dying on the operating table is shocking and compelling literature, but this time, it's not fiction. A boy literally died and then, through medicine and science, they resuscitated him.
The irony of Colton's "heavenly" experience of death
Ironically, death did not bring darkness and misery to Colton. Why is that ironic? Because when animals feel they are in danger of dying, they suffer tremendously. So, why should Colton's death be so gentle and sublime? One potential answer is that Colton's psychology was only so developed—he was only three years old after all, virtually unexperienced. That's another reason the parents allegedly believed it was creepy when Colton started walking around talking like Jesus.
The irony of the Christian imagery
A reader who knows that this family got famous touring churches (they even made a movie)—such a reader might be skeptical to even look at Colton's vision of heaven, but ironically, it's actually a little offensive potentially. This is because Colton (innocent, uninformed, and having never read the Bible) reports that when he "died and went to heaven," Jesus let him sit in his lap on the throne of God. That's language that packs a punch in terms of religious claims. Ironically, this boy's epiphanic message from heaven is quite difficult for traditional ears to hear. The story is inherently offensive, potentially to everyone.
The ironic strangeness of life
Ultimately, the single greatest irony is that the parents shared such a personal story, understanding that their critics would be unbelievably ruthless. They had to know the story would seem crazy, but they still published it and argued that Colton's experience was like sacred truth from heaven. Why? Because life got way too weird for them to explain otherwise (although it isn't like they tried to be scientific). Is "Heaven Real" as the title suggests? The book points to the ironic synchronicity of reality. That's a literary way of saying that life is sometimes so baffling and confusing that it seems like reality is being designed by an artist or something (at least, that is the religious interpretation).