1. what industry is he in?
2. what language or languages would it have?
3. what is the main purpose of the site?
4. what is the demographics of its audiences?
5. is it strictly graphic design or also system design?
6. does he have all the contents figured out and written?
7. going deeper into likes and dislikes: show 3 web sites you like from any industry. show 3 you really hate.
8. same as 7 but for your own industry.
9. do you have a company graphic language set? which colors and fonts does this language include? (if there is no graphic language - no collateral or letterehead and business cards at all - check what his anticipations are in this area, since the site and the rest of the communications should speak the same language).