I manage a small team of florists. It's a relatively peaceful, low-stress environment. However, one of my employees has recently been getting into pseudoscience and I can sense it trickling into work.

The most recent thing is that she's worried about the fiberglass insulation in the ceiling and fears that we're all inhaling it, even though none of us have demonstrated any other symptoms (like skin irritation). She believes we should all be masking and keeping the front door open for ventilation despite the fact that the flowers should be kept cool. I told her that the other employees can make their own decisions regarding masking. That seemed to satisfy her in the moment, but the insulation thing is clearly causing her a lot of anxiety.

Although I allow the team to listen to their own music while they work, she regularly listens to YouTube videos by Barbara O'Neill (a quack "alternative physician" who doesn't have any credentials) and shares her revelations with the rest of us. It creates an awkward situation since no one really wants to engage in these conversations.

She frequently calls out sick (a separate issue that I have addressed) with various maladies. I have encouraged her to see a doctor but she is more keen on self-diagnosis and home remedies. As her manager, I can't force her to seek healthcare, but I am concerned that this will escalate.

What's the best way to tactfully shut down these discussions in the workplace? We're a small, all-women team, so occasionally health and well-being topics will come up in casual conversation. But I have no idea how to manage someone who is so far removed from reality.