Do you think the "things to look forward to" would incentivize your parents to focus on clinging to life at the expense of drastically increased suffering and plummeting quality of life, or on maximizing the quality they still have at the expense of losing some months or years?
Even if you are still in good condition overall, at that age you know you're probably running your last lap and the things to look forward to are nowhere near as satisfying as they were even a few decades earlier. You can always find joy in the little things but they're always shadowed by other inevitabilities.
Many healthy years to you and your family.