Hostile environment, or just finicky bosses?

Q: “An employee came to human resources to discuss what he feels as his supervisor creating a hostile environment. He stated that his supervisor always brings him into the office about mistakes such as, ‘You left a comma off, you misspelled a word,’ etc. Also, as an example, he stated that he received approval by the CEO to have an event onsite. He was written up because he did not inform his supervisor about the event. The supervisor was on vacation and told him that he should have sent an email as a heads-up. The errors that he was written up for had no impact involving monetary, legal and liability to the agency or employees. He received an Above Expectation rating for the last performance cycle and a bonus; a year later, he was informed he was performing at 75% as a result of errors. He understands the definition of hostile environment. He feels it is hostile because it is interfering with his role as a supervisor and how he provides management oversight to the staff and department. What should be the next appropriate step?” – Anonymous, Virginia