I met with my nephew and his fiancée again for coffee and it was great. They are both wonderfully supportive and were genuinely interested in learning more about trans issues.
She brought up a work colleague who was married and liked to cosplay with his wife. He would always dress up as female characters which then segued into the question of the differences between people who like to indulge in gender non-conforming behavior versus those who are all about their intrinsic identity. This is the way I explained it and she understood the difference which made me realize that a lot of people who are very well meaning do not always readily make these distinctions. Just like the difference between gender identity and sexual plumbing continues to confound some people.
The thing I loved about their curiosity is that they were very open to learn versus people who are closed minded and only want to accept their versions of reality which is the malady of times.