OP I'm sorry you've been put in this position, especially while your Mum is out of the country.
We had similar discussions with hospital doctors re my Mum. They had had the conversation with her first, but then asked me about it separately as I have PoA and whilst Mum has some capacity, they didn't feel she had enough to make the decision entirely on her own. I understand why you are upset that they discussed it in front of him, but perhaps they felt he had enough capacity to be involved in the discussion, if not make the final decision.
Interestingly, she had agreed to DNR. My siiblings ans I initially said no as she has a reasonable quality of life, albeit with dementia. The doctors explained that in the event that her heart stopped, resuscitating would almost certainly not leave her with the quality of life she had previously, would almost certainly result in cracked ribs, possibly then a punctured lung and worsening of her dementia. We discussed it first with a cousin who is a doctor. They reinforced that position. Both cousin and hospital docitor said what PP said - that the reality is not like TV and movies, and there comes a time when you have to let them go out of love and kindness, and with dignity. I'm encouraged that so many other people on this thread have been given the same information.
Whether you discuss with your Mum while she's on holiday or not is up to you. In my case, I was also away when the discussion was had and although it's not ideal when you're away, I was glad that my siblings did contact me. If you decide not to discuss with your Mum while she is on holiday, it's important that it is discussed asap on her return and that she speaks to the GP about documenting her decision.
To the PP who said Obviously it does depend on age and medical condition, but no way would I approve of a DNR on a OPA. But that’s my choice. why would it be 'no
way' - you said yourself it depends on age and the medical situation?
One thing that the DNR discussions did for me, as sad and difficult as they were at the time, was that I had to face the reality that Mum is becoming increasingly frail, her dementia is only going to get worse, and should her heart stop, we would not be doing her any favours by resuscitating. If that even should ever arise, I will cling on to the words 'out of love, kindness and letting her go with dignity.'
Keep talking OP if it helps, I know how hard and sad this situation. Is x