His reasoning is that any extension of life achieved is likely to be of poor quality
Has he met any over 75 year olds recently? Most of them may have minor medical problems but certainly not enough to stop them enjoying life very much.
We are coming up for 80 and are enjoying life as much as we always did. DH has slowed down a bit because he has had a heart attack and bypass surgery., but he is still working, still doing DIY, (but no heavy lifting). still driving. I am still in good health, medication limited to low doses of statins and blood pressure pills, and most of our friends are similar. Yes there are a few who have died already and one or two whose health does limit their life, but not for the majority.
If this man gets to 75, hail in wind and limb, which is highly probable, I wonder if he will turn down a short course of antibiotics, for some minor medical problem, I doubt it.