My grandfather says crazy stuff like "oh, but we will be in the grave long before this turns into a problem" whenever topics like this emerge at the dinner table.
Why don't you respond with 'you will, I won't' and see what sort of response you get? While I don't want to promote disharmony at the dinner table, your grandfather's gloom at his looming mortality is no excuse for endorsing the diminution of your life expectancy. That said, such frankness might well result in him allocating any legacy away from you in his will.
This is anecdotal, but your grandfather's attitude is entirely consistent with the pattern of people generally giving less of a fuck as they age, starting around their 50s or 60s.
Local populations can be impacted, but far more damaging is tilling and the commercial farm practices: https://www.sciencedaily.com/releases/2017/05/170508095152.h...