What is happening inside him that he feels inside “I’m an idiot”. What are his experiences. Just hear him, reflect back to him, so your experiencing ______. Do I understand what you said. How does that make you feel? Show empathy. I hear you, that’s is hard to deal with or that’s rough. Just let him be heard. Let his pain be heard. He has already hear your pain. Share yours instead with a friend etc. but not with him. Don’t try to convince him he’s not an idiot or say things that you think might fix it. He knows already your response, or he can ask you. After many times of listening you may hear things you want to know and understand him better.