If your stepfather wants first class literature that happens to be science fiction, get Margaret Atwood's
Oryx and Crake. Also, also pick that if he likes dystopian sci-fi. Atwood presents a much more believable picture of the end of the world than the likes of Orwell or Huxley (though of course they are also great writers).
If he just wants excellent sci-fi (great fiction with a good dose of science), get Isaac Asimov's
The Gods Themselves. Imo this is a better book than any of his
Foundation series and since it's a bit less famous there's a better chance your stepdad didn't already read it.
If he likes political sci-fi (that is, sci-fi with themes relevant to society), I'd recommend Joe Haldeman's
The Forever War.
An honorary mention, but if your stepfather is interested in either GMOs or Southeast Asia, definitely ignore my previous suggestions and get Paolo Bacigalupi's
The Windup Girl.
[REDACTED said:
]The Foundation series by Isaac Asimov is an all-time favourite for me. It's a little light on the "sci" half of sci-fi, but if the phrase "Rise and Fall of the Roman Empire IN SPACE" intrigues you at all, you need to check it out.
I guess it all depends on whether your future stepdad can tolerate a book that's basically all dialogue and scheming.
hey, Foundation has a great deal more "sci" than a lot of modern sci-fi!