You won't find a drop-in Python library to do this. Parsing C++ is fiddly, and few parsers have been written that aren't part of a compiler. You can find a good summary of the issues here.
The best bet might be clang, as its C++ support is well-established. Though this is not a Python solution, it sounds as though it would be amenable to re-use within a Python wrapper, given the emphasis on encapsulation and good design in its development.
