There are teachers out there who make tests that are completely disconnected from what they've taught or had the students practice. You could be dealing with that sort of teacher here. An honors class should have higher level instruction and harder homework problems to go with the harder tests. If this is not happening, that is a problem.
You need to see the tests. Why have you been unable to do so?
The teacher could easily be the problem. There are way too many teachers out there that do this sort of thing and have no clue they're doing it or why it might be a problem. Teachers aren't always right.
The students get the tests & essays back to look them over and then they are handed back and locked in the cabinet. It can be a real hassle to get to look at them. The party line is this is so they can reuse tests/questions. I could go in & demand the teacher show them to me, but I've been trying to let my son deal with this on his own. He doesn't want me to go in and make demands.
On a recent quiz my son came home and said the teacher did put an almost impossible (not really impossible just would have taken them hours) on a quiz. So she had given everyone who gave the problem a try, the points for it. I am not sure what to think about this teacher. She clearly understands the math, but I was warned about her by other parents of honors students. She has high expectations.. Math problems are to be written on in a particular way and points can be taken off for that. But my son has figured that aspect out.
The English teacher I trust, my daughter had her for her senior year. And his not "getting" literary analysis is less of a surprise.