80+ and still pulling a travel trailer or Fifth Wheel?

My 83 yr. old father-in law loves camping and still pulls his 36ft fifth wheel. He is starting to “slow up” and is considering storing it at a local campground. My wife and I are thinking he has done well to pull a camper until his 80’s and should have considered storing it a long time ago.

Anyone 80+ (or know of anyone) still pulling a travel trailer or Fifth Wheel? What is the criteria for “hanging it up”.