I wouldn’t have hesitated to call the school. You’re the boss — grammatical errors (especially 8!) are inexcusable.
I teach English at a private school (where we have standards) and have written a book, so my skills are pretty good. Those errors jumped out at me.
You're right, I should have called the school and kicked some ass. My wife was afraid that if I said anything, he'd single out my daughter, a straight A student, and give her a hard time.