I have had a number of people tell me that their family member was put to sleep with morphine in the same sort of scenerio and the family member feels terribly guilty and bad. Nurses tend to like to put patients to sleep. I would never leave an older person alone with a nurse. Always have family or private care nurse there.
There is no reason to put an unconscious person on morphine except to hasten death.
That happened to my mother, under hospice care while at home. I was only one family member out of many, and could not influence anything. I did not realize at the time 100% what was happening, but knew somethings was Terribly Wrong.