A lot of people would assume that their odds of being involved in two crashes
Their odds?! These are crew members. They likely looked a good number of these people in the eye and interacted with them before seeing them all violently killed in front of them. That's a profoundly traumatizing experience.
Additionally, our brains aren't wired for odds. A veteran is unlikely to be hit by artillery in the US, but that doesn't stop them having PTSD episodes when fireworks go off.
Its probably not entirely independent, anyone who knows these two were the only survivors of a crash will probably work to ensure things are extra careful unconsciously
To the contrary, the psychological reaction is likely “If the nearly impossible could happen to me, the chances are much higher than I thought.” It may not be correct, but traumatic experiences don’t exactly lead to rational thought.
To be fair, the way he worded it called them NOT fragile. I think he has a point. We don't know how they are mentally, some might be fine, some might be not. Ascribing the way we think we would feel about it to the survivors feels wrong somehow.
A lot of people would assume that their odds of being involved in two crashes are basically zero and go on working.