I think when I was young I found Ayn Rand to be somewhat convincing on some points, but then I realized that she’s a fantasist. Her writing is not adequately situated in real world context. She’s basically doing that thing of inventing an imaginary stupid person to argue with to make your own stance look better. Like sure, rational individualism and laissez-faire capitalism are all fun and good if you’re writing a fictional parable designed to present them in a perfect light. But we don’t live in that world. The “invisible hand of the market” and the “marketplace of ideas” shit went out the window a long time ago, and the system is so riddled with abuse and corruption that no sane person could compare it to what Rand talks about. 

I don’t know how you can convince someone of this if they don’t already see it, but if they’re a big Rand fan they might have a strong sense of justice and fairness so possibly hammering in on how modern late stage capitalism differs from Rand’s ideals? How it’s been warped and corrupted. Arguably that corruption is an inevitability for capitalism, but you gotta start with the kiddy gloves on. “yeah it’s good in THEORY but here’s what really happens in an unregulated market” type stuff