Just so you guys without a National Health System which is free (well, we pay for it in taxes but not when we need it) know, the parents don't have to pay a single penny for what is happening.
Given the choice between spending limited public funds on a poor baby that will likely die or live in agony, and treatments that will save lives of people or transform their quality of life, I know where the money should go.
If the parent's object to the decisons of trained personel who have to balance the needs of individuals against the needs of other patients, whilst considering likely outcomes, then they can go private; it is very unlikely that doctors would go to court to withdraw treatment of a paying patient.
Seems to me the kindest thing would be for mum and dad to be handed their baby unplugged from all the paraphinalia that keeps it alive, and hold it close whilst it slips away.