When it comes to family, plausible deniability is the watchword (or two🙂 I'm sort of in the middle of the gender spectrum, but always use the women's bathrooms because I'm post SRS. I'm out about it to everyone I know EXCEPT my elderly father, who came to visit us a few months ago. We'd go toward the bathrooms at restaurants, gas stations, etc, and I'd just laugh and say see ya on the flip side and pop into the ladies to do my thing before he could say boo. The first few times he was a bit shocked, but I laughed it off and said it's always cleaner in there (NOT true; I'm looking at you, hovering dames) or some other thing. As long as it gives them the slightest reason to believe you're just screwing around, they'll jump on whatever reason you throw out there and be fine with it, for no other reason than being transgender is so outside their normal thought processes that it won't be the first thing they think of. Good luck, brother! 😉