I’ve had some success pointing out the situational awareness all women have had to develop since the age of 10, but consciously and unconsciously.
He was raised to be chivalrous, eg walk on the outside of the pavement, always see a girl/woman home safely after a night out. But I think it was an eye opener that our personal safety isn’t just about walking down unlit paths at night - it’s a constant radar evaluating men in my vicinity. That a random “smile darling” can turn into a vicious verbal attack or worse if you don’t respond in the “right” way. Choosing the right seat on the bus or train or in the cafe, making eye contact or not, when to remove yourself from a situation if you feel uncomfortable even if you can’t articulate why you feel uncomfortable. And none of this means that I’m in fear when I’m out in public, it means that I’m vigilant and aware.
I think he’d never really thought through the consequences of women being physically smaller and weaker than men.