Agree that anything could happen to anyone. How they invest, spend, gift, etc. can change their outlook. However the point of the podcast also hits on the theme that a frugal person is unlikely to become a spendthrift. And loosening up a bit doesn't automatically mean financial ruin.
I didn't listen to every second of the podcast/video but I was slightly surprised that this couple has real estate debt. There's nothing inherently wrong with real estate debt in retirement, if easily manageable but I would think that a FIRE couple would not have any debt. I'm in my mid 50s with only a low interest mortgage debt. I know it makes mathematical sense to not pay off my mortgage early but I don't want any debt regardless of the math as I get to 60. There is something about not owning anyone that appeals to me. My plan to save for the payoff and then make that decision at one single point instead of frequent additional payments. Or maybe I will sell before that time, and buy a new house with cash.