One way to deal with grammar obsessed students and parents from the past century is to hand them a grammar book. I did that last year at the American Embassy School very successfully. Here’s how it works:
The grammar copter hovers in during the first parents meeting around October and inquires politely, or not so politely, as to why their child isn’t conjugating more verbs, since they themselves did that and it worked for them when they were in school.
(At which point you say something to them in the language. Or you could do one of Robert Harrell’s tricks of slyly asking them to conjugate the verb to be in English in the third person plural form of the present subjunctive. That usually stops them. If you are in a gnarly mood, point out to them with an equally sweet smile that it might be possible that they mistook success in the language they took in school for the A that their grammar copter teacher gave them for memorizing verh conjugations.)
Anyway, just hand over the grammar book and tell them that since you don’t teach from a grammar syllabus – that nobody does that anymore – and ask her (grammar mom) to make sure that her child do the following (open table of contents and start circling) by the end of the semester and to check in with you every month to monitor progress.
I have found that the child rarely wants to separate from her classmates during class to go back to the back of the room and study grammar. Everybody is having too much fun! Last year my most difficult student, from England, ended up being the greatest cheerleader in the room for stories by mid-year, as well as a great second (coloring) artist.
I had given mom a book for her child to work on at home, and when I inquired as to how it was going at the spring parent conference, the mom looked at the child with a foreboding look. She had forgotten and so had the child to work in the book. I was off the hook!
This puts the ball back where it should be. With the grammar copter parent.