I suspect I must be about your dad’s age, and I don’t have problems changing up vocabulary a little bit.
You know, one more way to look at how easy and natural they/them can be is to examine how they’ve been used in a neutral sense all along.
In colloquial English it’s very ordinary to use they/them in the singular, indefinite sense.
In other words, if we refer to an unknown person, we often naturally default to they/them.
Check this sentence out, for example. “I saw this person at the grocery store yesterday. They weren’t wearing a mask but they were going through all the vegetables breathing on them. Yuck!”
That’s a perfectly natural English sentence, and it would have been even in the 60s and 70s when I was growing up. Well, we wouldn’t have talked about masks then. ;-)
The only real language jump we take when we move to using they/them in the singular is when we use them for specific people rather than for indefinite people. That can feel unusual.
But at least for me, reprogramming my brain has been easier thinking about how the use is so natural in some circumstances.
For me, it feels like a much less radical change, and making it automatic has become easier.