I'm not suggesting she look the other way, by any means. Looking at is as a "guilty until proven innocent" situation is, in my opinion, not the way to go. Making discrimination accusations is serious business...you better be DAMN sure that you can back up your claim. Also, if she's quitting - the people who are staying should be the ones to make the complaint...you know, the ones who are actually affected by the "discrimination".
If you're quitting - I don't really see the point of reporting anything. I would however, make sure that your current co-workers that are being discriminated against know it's happening (if it's happening). You may consider the fact that there may not be any discrimination going on at all...can you prove that some employees are making less than their male counterparts based solely on sex and not actual merit, contract negotiation, or earned bonuses? (I know I have been in more than one situation where I was making more not because I'm male - but simply because I asked for more)
We deal with this sort of thing all the time. The best move, I think, would be to be very upfront about how competitive the particular market is and your thoughts on that. And be VERY clear about the scope and what he's getting from you. onion2k is right - when he's not getting the traffic he imagined, you're gonna be on the hook for the "fixes" necessary to make that happen.