DNR

My father, shiyichyeh, (79 years old, very obese, history of heart failure, cardiac myopothy, orthostatic hypotension and at least one previous heart attack, along with other medical issues including chronic unsourced anemia, a large inoperable abdominal hernia and widespread arthritis) is currently hospitalized with sepsis and, apparently as a result of that, another heart attack. His last echo 6 weeks ago showed an ejection fraction of 15%. The doctors want him to be a DNR/DNI, as does my (non-observant) sister who is a RN. My father is lucid, communicates well and enjoys living even though he has been bedridden in a nursing home for the last 2 years. He wants to live, but not to be tortured. He would allow any type of resuscitation as long as it had a real chance of success, and again told this to his doctors today. The doctors insist that life after resuscitation for him would be terrible, that he would never get off a ventilator (even though earlier today he successfully got off the bipap they were using to vent him after being on it about 30 hours), that he would most likely need constant sedation to handle the tube to his lungs, etc., and that he would need to move to a non-Jewish nursing facility and be separated from my mother, shtichyeh, (who is living in the same nursing home he is). He is currently getting levo and dopamine to keep his blood pressure at an acceptable level.

What is the halachically correct course to follow here? Should he be a DNR/DNI? Just a DNI? Or should he remain a FULL CODE? How do 'quality of life' / pain issues impact this? We're under tremendous pressure to make this decision immediately and, as you might imagine, all of that pressure is to reclassify him as a DNR/DNI.

Thank You,