Sorry tarv.
No way in Bob's green earth I'm going to comment on a specific case where there are a bajillion factors that govern the diagnosis, prognosis, and subsequent decision to treat or not.
Just for starters, a 'heart attack' can mean many different things; beyond that, other purely clinical factors include Body Mass Index, Cholesterol levels, respiratory function, tolerance to transfusion, tolerance to anaesthesia, blood group, clotting ability, glucose tolerance, mental health/strength. . .
Therefore, please note the following are generalisms, not references to any individual.
Decision to treat is primarily based on the benefit (to the patient) of treating, versus the adverse impact of the treatment. Occassionaly, cost is a factor, but extremely rarely. (One headline a week about unaffordable care among the millions of patients treated each day makes the public disproportionately alarmed, but it does sell tabloids).
Low benefit vs high adversity means that providing treatment is often considered inhumane (and yes, I do mean 'often').
Intensive Care is an appalling experience for a patient and their loved ones, introduces new risks of Hospital Acquired Infections, and is usually (apart from trauma cases) reserved for people who are on their way out anyway.
If a condition is advanced, irreparable and terminal, treatment has to be palliative (I.e making the final stages bearable, usually through Pain Management), restorative (I.e. improving the quality of life), or remedial (I.e delaying the impact of the condition itself).
A hypothetical scenario based on real recent decisions:
An 89 year old with advcanced dementia (no clue what's going on) and a terminal cancer with low life expectancy (a few weeks) develops a renal failure. Would you put threm though a gruelling regime of surgery, medication and blood therapies for their last weeks on earth, or manage the end stage of their life to allow them to die with dignity and free from pain, in the care of their loved ones?
The only comments I will make on the tragic situation you describe are that I find it extremely unlikely that cost has even been discussed or considered as a factor. Any combination of just a few of the clinical factors I mentioned at the beginning (and numerous ones besides) could mean that treatment is not a kind or sensible option.
Finally, I'm really sorry to hear about this family friend, and that she's been unfortunate to contract such a serious condition. I'm confident that the decisions taken by her consultant will be based on her interests.
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"I started out with nothin' and I still got most of it left" - Seasick Steve