I think I can see two things going on here. 1. He hasn't gotten over and accepted his stutter. He doesn't sound confident being able to talk about it. He should be open and willing to answer all your questions himself. He still has some ways to go to develop in this area. 2. Judging by the way you've written about it, I expect you have not broached the subject in a positive way, though you have good intentions. Most people don't like unsolicited advice, and it seems you've been giving it to him without having a real understanding of his situation. Ultimately, he needs to accept and get over his stutter, but that's his journey. The best way you can help is to be supportive, compliment him, encourage him and help him love himself. If you are trying to "fix" him too, you will likely only magnify his self-hatred.