Well, I'm not an instructor (yet), but I have been a student, and a scared one.
You need to find out exactly what he's frightened of. A cross country involves so many things, from navigation, to talking on the radio, to coping with procedures at the other end (if it's a landaway) to dealing with weather, to being ready for emergencies. He may not be sure himself, in which case he has some work to do, while on the ground, to identify the problem. He may know but be afraid to tell you; for instance he may be convinced he's the only person ever in the history of aviation to be terrified of talking on the radio. Whatever the problem is, you can both deal with it when you know what it is, but possibly not till then. And he needs to know that too.
------------------
Whirly
To fly is human, to hover, divine.