As a random suggestion to get him thinking about defenses - make them visible for a session or two. It's easy to do in Maptools, and has a couple benefits (the PCs don't have to ask if they hit or not, they more quickly do powers, etc).
Once he gets thinking 'Fort attack vs fast stuff. Ref attack vs big stuff' kinda thing, he'll probably improve drastically.
The player and I have come to the conclusion that the next magic Item he finds will be a foe stone, as suggested in this thread- thanks again.
The point was brought home in the last session when two of the other players decided that they needed more info and started rolling skill checks to figure out what defences they should target.
I've also provided heavy hints in my descriptions of the bad guys- nudging the PCs in the right direction.
We're getting there.
Thanks again.