I second Anarcho-Bolshevik’s Michael Parenti suggestion. I’d also recommend searching his name on YouTube. Every lecture is gold, and 3–6 lectures is guaranteed to turn anyone communist.

If they’re open minded enough to hear what Marx has to say, David Harvey’s lecture series on reading Capital is good. The first few episodes, he just gets the class warmed up and uses some concrete examples to show how Marxism can highlight and explaining things that are otherwise invisible or impossible to explain.

I could be wrong, but IIRC, but in the first or second video Harvey talks about Anarchism and explains he is a Marxist not because he rejects the ideals of Anarchism per se, but because Anarchism does not have satisfactory answers for questions like, ‘How do we ensure food reaches places where there are famines?’ Again, I could be very wrong about the source for this point, but if I am, you’ve got your comrade to listen to 2–4+ hours of a discussion about Capital.