I agree with everything you said. I quibble with the continued over simplification when you move from speaking to the child to speaking to adults and actually the same issue is present in the child conversation. Too much victim blaming. The cancer could just as well arise from the free will of others. The child may have not made any choice that caused it. The parents may not have made any choice that from a causation perspective caused the cancer if for example it was caused by a corporation's decision to pollute. Sure, the parents chose to live there, but that is not causation, proximate or otherwise. Then, there are the cancers caused by viruses, etc., etc.

I watched a show recently, After Life, which once one gets past episode 2 is full of spirituality told through the eyes of atheists. I wrote about the show here: https://medium.com/promptly-written/spiritual-prompts-5-29-thru-6-4-2f65ac86dfcf One quote is particularly relevant to this discussion: “Good things happen to bad people. Bad things happen to good people. It’s not always someone’s fault.”

Does the Uranthia Book teach that life is improv scripted to create certain experiences? Does it teach that perhaps the soul of the child agreed to contract and die from cancer as part of its life plan because perhaps that is something that the lesson plans of the parents or others who would be affected by the loss required? My point is, yes free will absolutely exists and usually God/angels/spirits won't interfere, but your attempt to explain everything that happens through free will just doesn't work.

PS: I was asked not too long ago to explain my beliefs as I would to my non-existent 6 yr old grandchild. I discuss what I came up with in a few stories. This one is particularly relevant: https://medium.com/know-thyself-heal-thyself/how-do-you-define-god-9898492eae9