What do you think is a good candidate for such a statement? My impression is that arguments must proceed from axioms, positive axioms aren’t helpful because the statement is normative and normative axioms just reproduce the issue.
> medical ethics is a prescriptive and lexical ethics, one that you must follow if you are to practice medicine.
What is the meaning of “lexical ethics”? Google didn’t return anything helpful.
I believe the essence of the claim you are making is that, “There is a powerful enforcement body that will only permit doctors to practice medicine if they do no harm and render treatment in accordance with their means.” I think this a positive claim about human behavior, a proposition potentially belonging to the set of sociological or historical facts.
I suspect the family is talking about the way things ought to be, “Heart transplants should go to good people”. And you are pointing out that the doctors are responding with a positive claim, “That’s not what we do here.”?