One part of Agile that may help here is continual incremental delivery. If you can deliver new functionality to your client each week, a little each time, then

One part of Agile that may help here is continual incremental delivery. If you can deliver new functionality to your client each week, a little each time, then they should be happy to see progress, and each week you could re-evaluate how many weeks there are to go? Just a thought.