I think it is important to add that this should become a broader departmental discussion, not a discussion of the OP's instruction. My advice to my colleagues in similar situations, and to the OP, is to be very willing to hand over all course materials - WHEN EVERYONE hands theirs over, too. Make this about open access to teaching materials - department heads should not differentially police one member of a community. I suspect the OP is member of a different group - either by ethnicity, or gender, or training, or focus area. This kind of preferentially "looking over your shoulder" is one of the ways in which academia supports unconscious bias. And, it is a form of bullying, whether the forum recognizes it or not.
This.
He is trying to bully you by not coming to you as a colleague and seeing if you can problem-solve together.
So you turn it back by acting like a colleague. "Oh, Howard, do you have a concern? Let's get together, each bring our syllabi and perhaps a list of essential topics, and make sure that the students are getting what they need between the TWO of us." About the chair, act as though s/he is PART of your three-person curriculum committee. This is a small-group assessment - or no matter the way the doofus tried to frame it, you can act that way.
If, in the meeting, he tries to make it about you, you, you - turn it back by saying, "This is what I do to draw students into office hours. What strategies have and have not worked for you? Oh, you have none? [turn to chair] Millicent, from your experience, what helps draw students into office hours?" You indicate that students act professionally in your class and you haven't had those high school problems. But Millicent, if Howard is having those, do you have any recommendations for him?
