I believe there was prior discussion on adding an “staff must approve all posts by this specific user” feature, but I’m not sure it’s on the development calendar at the moment.
To me, this particular situation seems like a straightforward moderation task of directly contacting the user and asking them nicely to change their behavior, not something that needs a whole feature? And this can be enforced using the suspension tools.
In the meantime, what you can do now is lock the user to trust level 0, which will put some limits on how often they can post.