There was a case like this in my state a few years ago. The parents refused treatment for their son and were treated like criminals, everyone was trying to force treatment. They had to evade the authorities and hire attorneys, it was ugly.
Last I heard his most recent tests came back normal, no evidence of leukemia anymore with no treatment. He may have been lucky, but remember the treatments
for most cancers are risk factors
for the cancers. So if you don't really have leukemia before chemo, you may have it after.
The parents are the legal guardians, it would be wrong if they were refusing treatment for a broken arm or leg, but maybe not for something as risky as radiation and chemo. It should be their choice.
My brother sure suffered through the chemotherapy 25 years ago with a 50/50 chance of him living. Seeing what it takes to go through that at 8 years old, if my son had the same odds now I would probably decline treatment.
They have improved the survival rates they say, but until we actually have an Iinformation Technology system in place to accurately track treatments and outcomes in the clinical setting the numbers aren't that accurate.
It's a tough decision any way you look at it. But the government or hospital shouldn't force you to subject your child to those treatments, it should be the families choice in my opinion.