Yeah mine comes and goes with different severity. Usually, if I don't try controlling my breathing, it gets worse. Being nervous definitely plays a role, but not just that, being in a public space with people all around me is very nerve inducing for me too haha. It will definitely improve the more you guys talk. It won't ever be 100% fluency but it will definitely definitely improve. It will definitely get to a point where you two can connect better. Try ask him how he feels about people finishing his sentences or his past experiences. Talking about it does help somehow.