It was originally motivated by a question about probing apps written in perl as multiple, inter-related source files; I'm sure there are many coding styles where it doesn't work so well -- for example, I didn't give much consideration to OO-style modules and method calls -- but there is a chance it might help you a little. Just save it and run it on a set of perl scripts and see what you get.

(update: I just tried it now on a module I'm working on this week, and decided I should change two occurrences of  /^sub ... to  /^\s*sub ... (should be okay for work when sub definitions to be intended are indented) -- that old node has been updated accordingly. I'm sure other tweaks would be worthwhile too.)

One other update -- something that needs to be said to the boss: The code should have been documented when it was written. An important correlary to that point is that, if people are writing code for this person at the present time, those people should be writing at least some documentation -- and someone like you or the boss should be checking it -- before they write code. The code itself should be written to follow the specs as laid out in the documentation, and if that turns out to be a problem, the docs need to be fixed and rechecked.