You can't start conversations on communism by using the word communism with reactionaries who lived an entire life under anticommunist propaganda.

Assuming he makes a living as a worker and not by being a landlord or business owner, you can instead have discussions about how it's in his interest to ask for more pay for less work while the boss wants less pay and more work this creating the class conflict and how the owners of companies make billions more without working a billion times harder and that's how they exploit the worker.

You can also point out how wages stagnate and inflation increases and nobody in the gov does anything about it and yet the rich get richer. Where does the money come from, from whose value is it stolen from, ect.

Just avoid all mentions of buzzwords like capitalism, communism, ect as reactionaries have no values and operate entirely on buzzwords and what they're told is good or bad without an ounce of critical thinking.