What is your experience? Do you have investors? Security/code auditors? As the last poster said exchanges are ideal hacker targets. Unless you're going to do this with a professional team I'd say don't bother.
If you'll read what he's really looking for, he simply wants someone that has programming experience that can work for his exchange to pair bitcoin cash. Security is different thing on that and I guess he knows what's he's doing so if you are not the one that he's looking for better try to give him some nice place where he find great people.
@Gary look at services section
https://bitcointalk.org/index.php?board=52.0