To be fair to raw, I do understand where he's coming from..
I used to consider myself just an agnostic. Then I spent some time talking to atheists,
After that, the important part, I took time talking to atheists and ACTUALLY LISTENING to what they were saying, and it just seems like he's not to that point yet..
I look at it like this, in a 100 level class, you might learn that there's atheist, agnostic and theist... But after you get through that, in the 200 class, you learn, while that is kind of correct, its not really enough, and there's more info to cover, and then they break down what gnostic, and theist actually mean, and how the two aren't mutually exclusive..
Give him time, and once he starts reading for comprehension, instead of reading just to form a reply, maybe he'll see the point you're trying to make.
..I have some hope here.