I am acutely familiar with hospital systems and in every one I have seen so far, you can modify demographic information.
Maybe the nurses didn't know how to do it, but it can definitely be done.
Not saying there aren't other glaring inefficiencies (outsourced useless IT helpdesk especially), but changing patient demographic info is not one of them.
As a UX guy, you would surely vomit or run away if you saw most of the health programs I've seen.
Please help fix them, there are so many examples of shocking UI in health. So many of them look like first year uni projects by middling level programmers.
Also, sometimes only particular people (probably Admissions Dept) would have the permissions/knowledge necessary to edit that info. So maybe the nurses couldn't fix it but surely there would have been people in that hospital that could have fixed an incorrect name, had they been notified. They were probably who made the error in the first place!
Maybe the nurses didn't know how to do it, but it can definitely be done.
Not saying there aren't other glaring inefficiencies (outsourced useless IT helpdesk especially), but changing patient demographic info is not one of them.