Yes, he had a tantrum and quit working on the app. But, Facebook just put some other programmers on the project. Programmers are like flies these days...they are everywhere. We won't notice a thing......
I doubt that has anything to do with push notifications. The server development required for Facebook to push the notifications was probably outside the scope of the iPhone client developer anyways. Most likely, it is requiring the work of a group of people and I doubt that has changed.