Pretty easy. Get them to talk about a project they've managed and start poking holes. Who was on the team? How did they organize meetings? What were the bottlenecks? How well did everyone get along? What did they do to help grease the gears? Did they have to change the process? How did they like the software? Which software did they use? Did they have to administer it themselves? How did they deal with management changes / team changes / tons of support requests / issues in production? Where did they draw the line between PM work and engineering work?
From witching other managers, and via LLMs, you can literally learn and interview prep for all those questions on and lie. It's not difficult.
Well if they’ve learned that much it’s a good thing.
The remaining piece is to speak with some personal references to verify they did some real work.