I had a teacher like this from Y2 up to and including Y6. She had an appalling effect on me, she said that I would be lucky to get a job as a lavatory cleaner when I grew up. She hit me and spat at me every day. I have no idea why my parents didn't remove me but there wasn't another school close enough. Believe me, I'd have boarded more happily as then I could have enjoyed my time away from school without the ever-present cloud of knowing I had to return the next day. I would have been happier stuck in school without the breaks at home which simply reminded me of how life could be if you're not being spat at, hurt, blamed for everything and unable to do anything right; taking my armour off on the bus home, but having to gird myself again the next morning along with my school uniform. I would have preferred to live without my family at all, than be constantly dipping in and out, I was simply unable to, I had not enough strength for it. I can't explain it, but yes, living at boarding school, no matter how awful it might be, would have been better than having to be with my family while trying not to let school taint my home.
Your son has endured a year. He can still recover his self-esteem, it's not too late. Please think very very seriously about what you're going to do with him next year, as it will be too late to 'save' him very soon.
It took me until my 30s to develop enough self-belief to go to Uni, where I got a First! If I had done that straight from school as I should have done my life would have been completely different.
As an adult, it is also quite hard for me to identify when I am being bullied so people do treat me badly, except most of my friends aren't bullies and do give me a warning when they see what I can't. It is very easy to make choices because they are familiar, and when that familiarity is bad - how I was treated at school - then you find yourself in bad situations, abusive boyfriends, bosses etc. This has happened to me many times, as it is not straight forward disentangling the bad bits of childhood from the normal bits.
At the same time, it can also harden you emotionally, such that you can be less empathetic to others' suffering and misery. I hope that I'm not too bad in that way, and most people seem to think that I'm actually quite kind.
I hope you can find a place for your son where he is encouraged and appreciated and he feels valued and important. He is young enough to be rescued. Home schooling is always an option.
And no, don't give the bitch a thing
There are few teachers who are genuinely awful, but she's one.