A tough, personal call. There's no right or wrong answer.
If endangering their life & others, maybe it's time for a long, quite, personal talk.
They took my ex's keys 2-3 years ago, she was 75 last week.
(before you judge, we divorced in 1988)
I'll be 77 next month, my G/F is 73 & we're still riding on 2 wheels.