That is how I started when I came back to cycling two years ago ... cycled only on the really really quiet roads, then pavements everywhere else, then gradually as my confidence improved started using bigger and bigger roads. The main mistake I made was that I should of read Cyclecraft much earlier, rather than 8 months after returning to cycle.
Why not help him to plan a route that is just near the edge of his cycling confidence on the road, to the shops or something that he can repeat and gradually gain some confidence on.