It kind of depends on what kind of stories he likes, in general...
But, off the top of my head:
The Lathe of Heaven by LeGuin
Flowers for Algernon by Keyes
Slaughterhouse Five by Vonnegut
All of those have interesting ideas that should be fun to talk about on a trip. None of them is very stereotypical SF, as in spaceships and blasters... They're all pretty much set on earth in pretty much the present day, though Lathe and Slaughterhouse do feature aliens. Though in neither case is the alien race actually central to the book.
If you want to go with something that might fit his preconceptions of SF a little better, maybe Ender's Game.