There are a ton of techniques to leverage strengths. One of my favorite is building a mental map of a walk through a location and using the visuals in those locations to associate with items in a list. It is a very common tool in memory competitions.

Here's a link describing the method:
http://www.mindtools.com/pages/article/newTIM_05.htm

Mind mapping is another tool that plays to visual-spatial + creativity strengths:
http://en.wikipedia.org/wiki/Mind_map

I'd definitely go with bzylzy on exploring methods and ideas with your son.