A reasonable answer.
The sad feelings at the death of a nearby person are less likely to be as extreme if that person has basic medical care coverage. And it will usually not be clear whether more technically advanced care would have prevented the death. Therefore, the associated utility externality is likely to be small or non-existent. One can therefore rationalize the purchase of additional advanced medical care insurance by the rich as an expenditure of their own money for their own benefits in the form of a somewhat smoother and easier life---the same class of benefits these richer people get in other areas. Since the people buying this advanced medical care can afford it, they won't die because of its absence. To the extent that the poor die as a result of the unavailability to them of some advanced technique, the government can add that technique to those provided by publicly-paid-for medical care.