My company is in IT100. There are close to 100 developers in this division worldwide working on multi-million lines of code. From my experience, a couple of developers, not necessary just two, wrote one million lines of code is not likely. I think what he means is currently there are only 'couple of' guys. Maybe they didn't start from scrach. In the past they might have outsourced part of the task, bought some code, hired some contractors, fired a lot of developers. Their project may have legacy code.
By the by, what is your project? 15000 line of C++ code is some significant piece of work. It can't be a school project.
Good luck.