I used to draw a ton of repeating geometric designs when I was in elementary and middle school. Math teachers these days might call some of them tesellations. Does the drawing encourage the good performance in math, or are they both effects of a high perceptual reasoning ability? I don't know, but encouraging graphic ability is something that could help him in a number of professions, including cartography, architecture, and some jobs we probably haven't even dreamt up yet.
You can improve the frustration/creativity ratio for him a couple of different ways. One of them is to search for isometric grids on the internet and print them out for him, or print one and copy. The kinds with just the dots, offset every other row are the best. You have no idea how much time I spent in middle school crossing two sheets of notebook paper, trying to get my diamonds just so.
If you have an iPad and let him have access to it (two huge ifs, I know), there is an inexpensive program called Inkpad which is fairly easy to use and surprisingly powerful. I wish I could go back in time and give that to my second grade self!
I started to add a little note here about how spatially gifted kids could help to advance big time research projects--as researchers, not subjects! I decided that one really needed to be its own topic:
http://giftedissues.davidsongifted....utting_Edge_Research_at_.html#Post140957