This situation reminds me of the contractor's crew that rebuilt our house a couple of years ago.
One of the crew that would show up was a guy probably in his early/mid 80s. After several weeks, it became apparent that we had to inspect whatever project he was assigned due to quality errors.
After we inquired, we found out that he was the crew chief's dad who had been doing carpentry for like 60 years. Out of respect, his son kept him on just so he would continue to feel useful and needed.
As the homeowners having to put up with his mistakes, that obviously put us into a bit of an awkward position. Complaining about his mistakes just didn't feel right, but, at the same time, I'm sure we were being charged the labor rate when his work had to be redone.