I heard 75% remission rate (there's never a guarantee that it won't come back), but really that's neither here nor there.
He's 13 years old and has enough of a learning disability that he can't read. He doesn't believe that he's sick. And apparently even the first dose of chemo was enough to make him refuse any more treatments. No, 13 is not old enough to make decisions for his own wellbeing on his own, but his parents support his decision.
Frankly, I hate that they are using religion as the excuse now, because they obviously did utilize modern medicine for him to be diagnosed, get prescribed chemo, undergo the first treatment, etc. It wasn't all decreed by the courts - they wouldn't have known he was sick if they hadn't sought modern medicine for the diagnosis.
I think the court has gone too far with this, but that seems to be the wave of the future.
The boy has made his choice, his parents support his choice and even if HE doesn't understand the consequences of his decision they do. It's up to them to explain it to him if he doesn't understand it.