Yes, well I'm glad you said it before I could. The websites of ZVV and SBB are usually the best place to ask for timetable information.

You can also find all the information you need (in German unfortunately) about the night buses, including timetables and maps at the same site - here [zvv.ch]

Maybe you should suggest to your friend that he gives you more useful advice when you have such questions, but welcome in any case.