But still, even if he didn't know beforehand, he figured it out very quickly upon arrival and then stayed for a long time for the money, so I agree with most of your point.
http://thesensibletechnocrat.blogspot.com/2009/06/third-day-... seems to imply that he started there in June 2009. http://thesensibletechnocrat.blogspot.com/2009/10/moral-impe... seems to imply he was still there in October.
... Ooh, and all four parts of the story of which the OP here is part 3 are together in one handy bundle at http://thesensibletechnocrat.blogspot.com/2010/03/dubai-and-... .
So, he was apparently there for at least 4 months and at most 9 months. I wouldn't call that "a long time" in this context.
Being moral about the NDA does not weigh up against working there in the first place, and I don't know what $16 K means to a high profile Dubai consultant, it may have been substantially less than the severance pay he was entitled to anyway.
(Since he appears to have been there for something like 6 months before getting fired, I'll hazard a guess that his severance pay wasn't all that spectacular.)
So the severance could be anywhere from $5K up to a very substantial amount of money. The fact that they're willing to pay another $16K just for signing an NDA suggests it was a pretty high salary.
Given what he's possibly done to their reputation (I don't know; perhaps everyone already thought they were corrupt and dishonest anyway) that he wouldn't have been able to do if he'd signed the NDA, I don't see that an explanation in terms of salary is required: getting everyone to sign the NDA greatly reduces their exposure to this kind of bad publicity.