Let me tell you a little story about what happened to me.
I was working in a big company and it was my job to work with a designer to make a fairly small graphics visualisation thing. I had a meeting with the designer and he came completely unprepared. During the meeting, he pulled about 5 or 6 vague ideas out of his arse and told me to implement them all, and then the follwing week he would come by and choose the best. I didn't do that of course.
Programming is great fun, but not when you are working with a slacker and you want to get stuff done.
I say end the relationship and let him find someone who is more serious about it, and likewise you can find someone who doesnt mind if things take a long time.
Awsh, got that chief. Good thing I learned to prepare a full GD Document, at least the basic game flow before talking to a programmer. The last project I've been working on is flowing like a charm, of course, I've applied all the lessons learned.