No, they are not capable of genuine discussion in their fully indoctrinated state the JW program running in their brain won't allow it. Garbage in garbage out.
That's why I feel they need some sort of "short sharp shock" in the form of saying something they will find completely unexpected to disrupt the JW feedback loop in their brain for a few seconds or minutes. Enough to allow a tiny window of time for a critical thought to get in that may resurface later after the conversation has ended. That's how most people wake up in tiny snippets rather than all at once, it's a process.