Although you do not give specifics about the “problems” created either within the person or relationally, it does seem, based on your observations and concerns, that something indeed is bothering the person. If it were me, I would gently—-gently—-approach the person with your observations. As an example, you might consider saying something like this: “I am concerned about you as a person. May I give you some feedback in the spirit of helping you? You keep saying that you are doing fine and that your anger is not getting in the way (personally or relationally). Please do not misunderstand me. You are a friend and I like you very much. Because of that, here is what I see as getting in the way for you: (you can then list a few—not all—of the issues and see how he reacts).” If he begins to see some of these issues, then you have come a long way to helping him. Thank you for your courage to try. Perhaps you will succeed.