Not if your going to do a career in it as he said.
As to needing to learn C++ anyway: not necessarily. There are plenty of libraries and platforms that can be used to develop games that don't use C++.
It is to an extent, when you considering everything is basically already implemented for you in C#, and more so in Python. I didn't recommend he code an MMO, instead of hello world, I recommended he stick to what he already has experience with.
Learning C# or Python first is not being "lazy." We don't start our careers coding MMOs, we code "hello, world."
That is not to say you cannot learn in those languages, you can, but you will be missing the finer details.