Character Analysis
The fact that Shaun's parents are divorced is one of the reasons why Kiriel chooses Shaun in the first place—he figures it will give him a lot of freedom. And the thing is, he's right. We only run into Mr. Simmons once, and it's only on the phone, but it makes a big impression on Kiriel.
After the call, Kiriel thinks, Shaun "would have been able to converse with ease, interest, and even excitement. He would have known what to do when his mother put her hand on his shoulder or called him an angel. He would have known how to respond to an 'I love you'" (19.138). Ouch. In interacting with Shaun's dad, Kiriel really appreciates how he isn't truly human.
Kiriel figures out there are some things Shaun would know that he doesn't, and this surprises him. Still, it has a positive effect, too—it inspires Kiriel to reconsider what he's doing on earth and start to try to change things. Perhaps without Shaun's parents interacting with Kiriel in this way, he wouldn't have thought about how he could help them out. But they do, and he does, and it seems everyone's the better for it. Yay.