I'm a nurse, so I've seen a reasonable amount of deaths, some expected, some not. I have no personal experience of death e.g. a family member.
To me a peaceful death is when my patient isn't agitated or in pain in their final days, and they're surrounded by the people they love.
The worst deaths I have seen are when the patient is dying, however would like to continue treatment, or the Dr wants to continue treatment and they then arrest and I have to attempt to resusitate them, very often unsuccessfully, it causes alot of trauma for the family.
We try to recognise dying as early on as possible so a care plan can be individualised and we try to fulfil the patients last wishes e.g. where they want to die, if they would like a chaplain, who they want to be there.
The last death I was involved in, I had looked after an elderly lady for a few weeks on my ward and she had been getting progressively worse following a heart attack, family were aware of prognosis however she wasn't put on the end of life pathway and we were actively treating her.
So I'm looking after her on my shift one day and she really goes downhill, I call the family before I call the Dr as I knew she wasn't going to last much longer. Whilst waiting for the family, the Dr reviewed and it was agreed she was dying imminently and was no longer for active treatment, however the decision was made to try and prolong her life long enough for her family to say goodbye. So that's what I did, I gave her intravenous fluids to try and raise her blood pressure enough so that she would remain conscious, she wasn't in pain at all and was very comfortable, but I was trying to keep her alive until the family arrived. The family arrived just in time to say goodbye, and we all stood around her bed, holding eachother whilst she slipped away. The family were so greatful they were there, they could say goodbye and see she wasn't in any pain.
To me that was a peaceful death, the actual end was very quick and she was pretty much conscious until the end, in absolutely no pain or agitation, surrounded by the people she loved.