I think your being a little to zoom in on the technicalities of modern day ai to tell the trees from the forest.
I am a bundle of connected neurons, effectively a neural network, i can calculate just fine.
Humans are “in general” horrible at doing math but thats besides the point of being capable of it.
Modern humans have a calculator in their pocket and we use it as a tool to make our own conclusions. Like ways “current day” ai often has acces to a calculator tool to do the same. Sure this is not ai doing the actual math but in practice its the same as a human with a calculator.
But the topic at hand is not even about current day ai but about hypotethical future ai that “somehow” is trusted enough to pull the plug on machines that keep a sick human alive.
Such future ai. If it would ever exist would have acces to such tools, possibly more complex tools to calculate odds of survival using (hopefully) a formula with a great number of input variables to consider all kinds of situations.
I would imagine such to be a known formula that humans could also independantly measure and calculate ending in a % chance of a survival. But somehow in this hypothetical future this would be a job given to ai.
So the question is less can ai solve math and more can we trust ai to interptet humam measuring tools to then put those values in a known formula tool to then act appropriatly on the results of said tool, and not at any point misalign/hallucinate.