>Can someone tell me if what this guy said is true or not? If so, how can you write a manual before at least a proto-type is done - in other words, before any coding?

In my experience, this is not true. Creating the manual before hand IMHO, would be counterproductive- requirements so often change during the application's construction, that the manual would likely be useless at the end of the job.

That guy sounds like a wierdo anyway.