Your son sounds like an excellent conscientious student.
Maybe he is reading a lot more into what she is actually saying to him.
Maybe he is projecting his own feelings.
Why would this teacher not want him to succeed?
Why would she want him to feel like a failure?
Consider
Maybe he is doing too many other things?
If he cannot complete his work he is doing too much.
or, Maybe he does not understand her instructions?
What grade /how old is your son?
In elementary school, you need to speak with her.
Middle school, you and your son should speak with her.
High school, he needs to speak with her.
Then if you or your son is not happy with her answers you take it to the next level. Asst. Principal.. or Principal.
He needs to take exact examples of what he is concerned about.
Example.. That he writes down the instructions and follows them, but she changes the dates or expectations. - This will need to be documented with proof. Her hand outs, her online instructions...
The basic school work should always be his priority.
If he is exhausted he is doing too much.
Our daughter was a student like your son.. Also not bragging, just giving you our example.
Took all classes all Pre AP and Ap classes.. all the way through high school. No early leaving campus her senior year. . Took extra classes in subjects she was interested in, physics, economics, etc.
She even decided not to take PE at school, but take it after school, on her own time.. even when she had fulfilled her requirements. She also graduated with a special study from the fine arts academy. As well as working 100's of hours volunteering. Was in academic competitions as well as art and music competitions. Traveled with the Rowing team around the country.
She was even published twice while in High School. She did this on her own time.
So I know exactly what you are talking about. I worried all of the time. I also reminded our daughter, I was not able to remind her or help her with her homework, all I could do was give her the supplies..
Our daughter learned to be extremely organized with her work. Just because a project was not due for 3 weeks, she knew that sometimes, she was going to be too busy to work on it in the future, so she would begin it early, maybe do a rough draft.. and then complete it when possible.
She might go ahead and read a book assigned, even though the teacher said to follow along in class.
And sometimes, she was just exhausted, so she would have to adjust her fun time and just stay home some whole weekends.
I know you want to step in, but if he is in high school, it is expected that he handle this with the teacher first. If this is not working he can ask the teacher to meet with him and either his academic counselor or the asst, Principal.
And then if he still does not feel they are hearing him, you go in with him..
I bet he will be fine in the end and this is some sort of communication deal..