Every stutter is unique. My own has nothing to do with nerves. Is he nervous around your family, or does he just stutter more? Stuttering can make very little sense in when and how it manifests, and it constantly fluctuates in most of us, even with what sounds cause us trouble. I want to be clear though that I'm glad you want to help. I just caution to really consider your approach. Stuttering isn't like working out to lose weight, and it's not like overcoming depression, which almost everyone deals with to some degree. It is ingrained in our DNA. I agree with brethal above. Make sure he knows you love him, and that you love him even if he can't say a fluent word again for the rest of his life. Make him feel more comfortable in situations he seems nervous in. Be the support to strengthen him. It's a fine line to walk and I'm not a relationship counsellor. A girlfriend of mine helped me very much with my stutter by in fact loving how I speak, complimenting my voice and always reminding me she loves how I sound and how I stutter. That made me more comfortable to speak in front of her and in all situations in my life. What you don't want to do is come across like you don't like part of who he is. That will haunt him and the relationship. My advice would be to have a conversation with him in which you express how much you love him and the last thing you want to do is criticize him, because you think so highly of him. Tell him you don't understand stuttering, it intrigues you, you want to learn more, you're interested in how techniques help him, the idea of working on it interests you just from your own curiosity, and you want the best for him and support him in whatever he does. Again it's a tough line to walk but if you make clear that foundation of unconditional love while broaching the subject, he might open up a bit more and you two can have a more frank conversation on stuttering.