Kudos to your FIL. Where I live we have a few people in their 90s who are still grooving along.
My late auntie Clare who died a couple of years ago, at a few months short of 100 wasn't as active as your FIL, but she did read the Daily Mirror everyday for over 60 years....that was her mantra :>
Regarding beragons, I made them as part of my service at Wringford Manor, the place where novitiate ashram premies went to in the early 70s.
They were not the curvy-type, but the straight type with a thick foam on the flat bit covered in red velvet. No soar arms from my beragons.
I did meet up with a honcho premie in the early 90s who told me she still used the beragon I made. I was a bit shocked because he had banned them years before...still, I didn't tell on her. :>