|A. His comments actually merit a "huh?" from you, but there may be something better to say. The problem is that you are going through a real disappointment, and all your manager is thinking about is himself and his new opportunity.|
Your manager must have a high score on the ego scale, as he seems to think he is the center of the universe, and all that really matters is whatever may be going on in his world. You have probably observed this type of behavior in previous dealings with him, although he many not have been as over-the-top as in this recent episode.
You can certainly tell him that you hope his new situation works out well. The next step is to say that you were not effusive about it because you were in the middle of a setback that you had wanted to discuss with him. Then stop and see where he goes with your comment.
If he still turns this into a conversation about himself, there is not much more you can do except hope that his new project will include a promotion or transfer.