I agree with both comments so far. People who are abusive are often not 100% bad actors, and they can be wonderful and charming when they aren't being abusive. In fact, one reason why battered women STAY in relationships is that he is Mr. Wonderful when he isn't beating her. He says he's sorry, he swoops into a honeymoon phase to woo her back, he makes all sorts of promises that he will change and he will never do that again. And then he beats her again. They are often described as Dr. Jekyll & Mr. Hyde. While this guy isn't beating your friend or threatening to kill her, he is abusing her.

As for what to do as a friend, just listening is wonderful. So often, people in controlling relationships end up cut off from all friends. This guy sounds borderline. He's "just" into controlling and verbal abuse. That is harmful to the recipient nonetheless, although she might never end up in a hospital ER with a re-arranged face. She could benefit from gentle encouragement to learn to be more assertive of her rights.

Cowgirl