As a doctor, I will not give patients treatment that is inappropriate. That includes futile interventions like attempting resuscitation in someone who will not survive if they get to that point.
I have attended hundreds of in-hospital arrests and have seen 2 people get well enough to go home. Most people who arrest in hospital are arresting because they are dying because they are very unwell.
Attempted resus is an undignified event. It is not like Holby City and nowhere near as successful! Instead I have to strip off their clothes, get someone to try to get venous access to give medications, someone else to try to put a tube down their throat, someone else to do chest compressions. It is not nice and so often inappropriate, when that person should be allowed to die in peace, comfortably with their family near them.
I will not ask for permission to do a DNR form, but I think it is something that needs to be carefully and sensitively discussed with the patient and/or their family (as appropriate). I will explain that the patient is very seriously unwell, that we are doing what we can, but, despite best efforts, they might not get better. If that happens, we will do all we can to ensure they are kept comfortable and pain-free and that the end is peaceful. I'm sorry that it sounds like that didn't happen for DartsAgain's mother.
As for euthanasia, I am completely against it, but I believe that part of my job is ensuring people have a good death, so I will do all I can to ensure that they are given all the pain relief/anti-sickness drugs etc that they need to ensure that their death is as comfortable as possible.
The Liverpool Care Pathway is a way of ensuring that the nurses have all the tools available to do that once it has been signed by a doctor. Again, I am not going to ask a relative's permission to use it, but those relatives need to know just how grave the situation is with their relative so that they can be prepared for what will happen next.