Background: I indirectly oversee a professional who manages an assistant. The assistant's work has lacked some attention to detail lately. The manager decided to deal with this by sending a rather scathing email berating the assistant for some mistakes that were made, and sent me and one other person a copy to keep us in the loop. I feel that the approach is not likely to be productive, and would like to guide the manager toward a more respectful approach.
Question: What is the best way to approach the manager to encourage a more respectful management style and by extension a better workplace atmosphere for all
And given that we probably can't afford to provide formal management training, Is there a book you can suggest that we could ask the manager to read to learn more about the benefits of a respectful management style?