The question is whether GCC is a good example of the benefits of C++ for compilers. Considering the code looks to 95% like C code and uses data structures that we originally implemented in C, I don't see this argument.
I told him the same thing multiple times, just open a random code location in GCC, or a recently committed change, and see that it's basically C. But he keeps repeating that ridiculous argument like a broken record.
Unless of course, you don't have anything to do, and feel like bootstraping GCC 16, using a compiler chain all the way back to 2012 thereabouts.