An ad in the NYT for travel to Pakistan is not evidence. Sorry you feel it is. And I have a brother who traveled to Pakistan in that time frame on opthamological business and his hoops to jump through—finally getting approval from Paklistan—testify that it was not a simple task to travel to Pakistan while it was under Martial Law.
Not an ad, but an article on travel in Pakistan, including the information on how to get a visa. Also posts from people who said they did travel to Pakistan and the link Deport posted in an earlier thread to the State Department's travel advisory. I'd be happy to see evidence there was a travel ban - it would make a stronger case. But what I've seen is evidence there wasn't, and your brother's situation is just more evidence there was no ban. I do not doubt travel was difficult as your brother's experience shows.