With emphasis on "regularly," I think you're right. Medical staff have joined the ranks of welders, carpenters, fire fighters, and many others who regularly wear N95s for their jobs.
Looks like they've been in use since 1972 and in use in Healthcare specifically since 1995.
It's not just N95s though, the above also mentioned disposable masks which is absolutely not a new thing in healthcare.
That's the grandparent, but he is talking to the parent and he is right to point out the error in the parent's post. It's a bit strange to think the parent would believe that masks are new to healthcare, consider the most plausible interpretation instead.