Fred's situation is extreme, but doctors assure him that the precautions he takes are sensible. One can try, of course, to keep oneself from getting into Fred's situation in the first place. Some early-music lovers leave when the rock 'n' roll starts. But they reduce the decibel level evenly throughout the entire frequency range. Also, they can be varied to reduce the decibel level to greater or lesser degrees.
Organs can do the same.
Still, in general, early music players and listeners have little to fear from their focus on music and instruments from the quieter past. The early music movement is sometimes criticized for its preoccupation with the past, but with respect to noise levels, the past has something to teach us. The economics of performance have changed and so has much else, and many of us wouldn't want to return to the lifestyles of medieval monks. But the music continues to speak to us - and it does so while respecting the natural limits of the human physiology.