Step-parents who overstep their bounds are such hypocrites because there’s no way, like 99 percent of the time, they actually give any real shits about their spouses’ spawn. The best arrangement for step-parents is where they’re support for the bioparents, not so much a surrogate parent, and where they’re only authority figures when the bioparents aren’t at home. Zach seems like the type where he wants his wife’s kids to pretend he’s a parent only when it’s convenient for him. Meanwhile, the kids undoubtedly see him as mom’s shitty husband.
Which is just great because the single greatest factor in a kid’s success in school is parental involvement. I’m sure parents are a pain in the ass, think of the worst customer except times a hundred and that’s your average parent at a parent-teacher conference, but that goes with the territory. If you can’t handle it, don’t be a teacher.