Perhaps you could arrange for a conference for you and Dad with the teacher. I would suggest to the teacher that she talk with the Dad just as she talks with you. Sounds like Dad is missing important information about the teacher and the classroom.
The Dad's response seems quite harsh to me even assuming that the Dad is acting on erroneous info that he considers correct. Being on the talking list doesn't warrant 7 nights of reading out loud and doing chores for an hour. First, reading should be fun. Reading should never be punishment. Reading could be a form of discipline if your son didn't get his reading done because he was talking. But then you probably know that.
I do not understand your ex's philosophy of parenting in this situation. What does he hope for his son to learn from this and how is his form of discipline helping his son to learn this? If you're able to discuss parenting issues with your ex then this could be a way to start.
I'm guessing you and your ex aren't able to talk about this. If you're not then the best that you can do is to help your son understand that his father has his ways and even tho you don't agree in this situation he still has to do what his father says. Then focus on how your son feels about it. Accept the way your son feels. Let him vent. Then help him find a way that he can make a difference. Perhaps focus on the talking in class. Brainstorm ways that he could help himself not talk so much. Focus on how the reading will help him improve. Suggest he find a book that he would enjoy reading out loud. And remind him that if he cheerfully does the chores he'll feel better even tho it doesn't feel fair. A bit pollyannish to be sure but he will find that looking in that direction does help.
My mother very wisely told me when I was upset about the way my father treated me that he was my father and was doing the best he knew how. She taught me to accept what had happened even tho I was upset, to talk about my feelings with her and then to focus on what I could do to make it different for me without expecting my father to be any different. It took me years to understand and even when I was an adult I was all too often upset over things I could not change. But the idea that some things are unfair and that I have control over myself and how I react is an important part of my life. Ten is not too young to start learning that.