That's not what happened, the tabloids made it up.
What actually happened was parents kidnapped a little boy who was very unwell with a brain tumour but was receiving excellent treatment on the NHS and had been given an 80% chance of survival, because they didn't want their child receiving chemotherapy. They claimed the reason they didn't want their child having chemo was because they were worried about side effects, but the parents were also Jehovah's Witnesses and there was speculation their religious beliefs were a factor in not wanting their child to receive chemo. Doctors reported that the parents hadn't allowed or had delayed their son from having routine tests and procedures, for example when he first became unwell they tried to prevent him from having a spinal tap. When his brain started to fill with fluid, they tried to prevent doctors from implanting a shunt to drain the fluid.
The parents were so desperate for their son to not receive chemo (even though doctors had estimated chemo would give him an 80% survival rate), they decided to kidnap him and take him abroad, ostensibly to receive proton treatment which they wrongly believed had fewer side effects. At that time the NHS had funded certain patients to receive proton therapy abroad but only in cases where there was medical evidence that proton therapy would be more effective than chemo.
Doctors in this specific case felt that proton therapy wouldn't be more effective than chemo and that stopping chemo would harm him. However, they were willing to put the parent's wishes first, so the hospital in the UK started to liaise with a hospital abroad to make plans for him to be taken abroad for proton treatment. So he WAS going to be given the treatment the parents claim they wanted, even though the doctors felt it was unwise.
Then the parents just kidnapped him and ran off with him (for no reason, since the NHS had already made clear they would support him going abroad for proton treatment) and when he was found they were hiding with him in a hotel having dragged him across multiple countries. In other words, they didn't take him abroad and take him straight to a hospital to start proton treatment. They just hid in a hotel. They also didn't bother to learn how to use his feeding tube.
The parents very nearly killed him by taking him off chemo and away from hospital care, and there's no evidence they actually planned to take him to a hospital abroad. By all accounts they didn't want him receiving any medical care at all. Their action in kidnapping him made his condition much worse.
The only reason he's still alive is because police found and rescued him and he was rushed back to hospital, and doctors had to step in and battle to save him from the extra damage caused by the parents carting him around Europe, causing him to miss chemo, and hiding him in random hotels when he should have been in hospital.
The parents actively harmed their child and their actions in kidnapping him reduced his chance of survival. An independent review found that the parents' actions had reduced his chance of survival by 30%.
He's alive in spite of their actions, not because of it.
And it's not a comparable case, since he was never terminally ill, the disagreement over treatment was over side effects not survival, and the parents not wanting their kid to receive chemo, and there's evidence that due to their religious beliefs they didn't want their child having any kind of medical treatment.