Might be worth checking if that’s the case where you are, because where I live that is most definately not the case. Regardless of the patients wishs the medical staff will decide if they are going to resus or not. I have seen it myself - DNR - or NFR - on patients charts, and this was most clearly NOT the wish of the family or patient, but the medics, knowing the likelyhood of survival, or the resulantant damage upon a further stroke, heart attack etc, took a clinical decision not to resusitate regardless. This decision is communicated to the family, with great empathy, but the familys view changes nothing.
Two years ago I was involved with the admission of someone I was looking after; the hospital staff were fantastic, but two days later, following deterioration, I got a call to go to the hospital, and it was explained to me that they make the guy comfortable, manage his pain etc, but they would not resusitate him; myslef and his aunt had no say in the matter. A clinical decision had been made and that was that. 3 days later he passed away.