I couldn't disagree more strongly. The parents and their son collectively agreed that he would not take a second round of chemo due to his reation to his first round, which had already failed. They made a decision the social worker disagreed with, and she or he therefore used the powers of the state in order to coerce them into a different course of action.
What is reasonable about that? It's an abuse of the system - outright declaration that the parents (and their son) do not have the right to make an informed decision about the care of their child. Why not allow social services to outlaw ice cream - after all, there are a lot of fat kids (and adults) who would benefit. Right?
The social worker didn't coerce anybody. She NOTIFIED the court of a situation that looked like it might constitute child neglect: a boy had what is generally a fatal disease if not treated aggressively, mainstream medical experts agree on what is the best course of treatment in most cases and that multiple rounds of treatment are often necessary; the boy had one round of treatment, didn't like it, and the parents were refusing to follow doctors' advice to repeat the treatment. It's not for a social worker to make a definitive decision in a case like this; her job was to notify the court of her reasonable suspicion that court intervention was warranted. The court intervened, consulted with medical experts, consulted with the parents and nearly-adult child, and the parties came to an agreement that the parents and child are apparently comfortable with.
We'd have a lot more dead children if social workers just blindly ignored worrisome parental decisions. Over the years several children have been killed, and more permanently brain-damaged, by parents who for either religious-whacko or new-age-enviro-whacko reasons insisted on keeping their infants/young children on extremely restricted (usually vegan) diets. When social workers encounter a thin sickly child, whose parents are yakking about stuff like "raw foods only" and "no animal products" and feeding the kid nothing but raw vegetables, it's appropriate for the social worker to alert a court, and for the court to intervene.