Maybe not as good as I thought... Upon further review, with the new pictures he posted, it doesn't look like a three-piece setup with a Hexon cartridge. It does look like a two-piece crankset. I hadn't seen one with a hexagonal spindle before, but sure enough, SR SunTour shows 'em on their web site:

Details - SR SUNTOUR Cycling

...and while I was poking around the site, I found documentation with helpful diagrams for installation and removal:

http://www.srsuntour-cycling.com/fil...-01-140514.pdf

He has to remove the serrated lockring on the non-drive side using something like a hook spanner before tapping the spindle through.