the fact remains that there are children out there who have a not much higher quality of life, and whose parents believe that their lives are still worthwhile
I posted about this upthread. I've worked with many terribly disabled children and adults with the kind of loss of function you're describing. But they were disabled, not ill. Their bodies dealt with damage and different functions as their normal, and they were mostly healthy and very much alive. This isn't about disability, it's about illness. Charlie's body has been trying hard to die for the last seven months. This is not about intentionally ending his life because it has no value or purpose. It's about the ethics of continuing to aggressively force a child's body to stay alive long beyond the point of any hope and to wring the last possible second of medically achievable life out of it no matter what the experience of that may be to the patient.
Ventilators are not gentle. Rescusitation often breaks ribs. There will come a point where no matter how many electric shocks and needles jabbed into the heart and drugs poured into a body that it will die even on a ventilator. As someone said further up thread, ventilation is basically stick the body on life support and see if kept alive, can it right itself or progress in any way. If it doesn't, and that further degeneration is inevitable to that last moment of death, is that how a child should be treated?
If Charlie was severely disabled but well, and that might be medication dependent, oxygen dependent and tube fed dependent, but well, then no one in the UK in particular GOSH who specialise in very profoundly disabled children and fight their corner very powerfully, would say for a moment his drugs or his feeding tube should be removed to cause his death. I hope very much this treatment can give him what very profoundly disabled kids get - to go to school, to go swimming, to enjoy sensory rooms and music therapy and the other things that I've seen make profoundly disabled kids and adults light up even when they could barely respond. It will be wonderful.
But I absolutely don't agree he should be aggressively treated to wring every last possible second of medically achievable 'not dying'. I can see exactly what is in that for his parents, but I can't see what is in it for him.