Hm, I really don't know about duty of care to parents/relatives of patients unable to speak for themselves. I too would love an opinion of a legally qualified person on that. Good question 
In society in generally there seems to be such confusion, fear and lack of understanding about natural death/dying and what medicine can to do defer death, ameliorate suffering or change a disease trajectory.
I think really interesting conversations could be had with great benefit to individuals but also society if we became better at talking about life/death, quality of life vs duration, suffering/merely existing vs living a fulfilled life.
My 84 year old father just had open heart surgery and the lead up to this planned operation generated many interesting conversations and musings - some practical (he updated his will, he made damn sure a DNACPR was in place, he made sure my brother and I knew where relevant documents were should he not be able to look after himself etc etc), some of them more philosophical: what happens when we die? where do we go? what is it that 'goes'? how much suffering would he accept as reasonable for himself for what kind of trade-off?
Yes, there were some tears, his and mine and my mum's, but also laughter and plenty of piss-taking and gallows' humour maybe just our way of dealing with being more than a bit petrified.
Death is a normal part of life. Without death there is no life. Not talking about it or a narrative of 'fighting' death or of 'losing' a fight when dying are not helpful in my opinion.
None of which takes away from the horror of losing a child - I don't think that the phrase 'untimely death' is wrong when a baby dies, whatever the circumstances
.