chances are that he has done this already for a long time. I would wonder about the possibility of repetitive stress injuries. With that many reps and sets per exercise, he probably only does a few, and does them every time he works out (pure conjecture).
As Natalie says, low weight and high reps are the hallmark of work on muscular endurance but I would not use that many reps and sets even for that.
It certainly is different from the general recommendation of using higher weight and fewer reps to build strength, and I would try to encourage the client to change. I would expect reluctance on his part, though. Maybe you can make some publications available to him like this one from the NIH which suggests a different way of training. http://nihseniorhealth.gov/exerciseandphysicalactivityexercisestotry/str…
Hello M.C. Doreen Rioux,
Is this person retired from work and/or has much free time? It should be fine. This is no different from a stock person loading shelves eight hours or more a day. This works muscle endurance. If the client seems comfortable, I would have no worries; although, I do not know this client’s history which may say otherwise.
Natalie aka NAPS 2 B Fit.