Map the problem into other domains. In this case, he could work with the original (hard to understand) source code. Or he could use a tool that would translate it (or the binary) into a more sensible language.

In other tasks, consider different data structures or representations that fundamentally represent the same data, but in different ways that offer different guarantees. Representing a graph with a matrix may let you answer some questions very quickly, but it may make others harder to answer, for example.