This is a rather broad and not very actionable criticism. Can you get more specific feedback? For example, something of the form "In situation X, you did/said Y, and that led me to think Z" is more actionable. Also, it is useful to pay attention to the classification problems that your engineer faces. There is a sometimes a balance between being condescending by giving someone info they already know and not providing enough context for an explanation.
The book "Thanks for the Feedback"  is a good read and Erika Carlson's talk from Lead Developer UK is a good watch.