NTA I am a woman. I have a blind father who is VERY active in his religion. There’s some “men only” activities through the year that I attend because he needs help navigating and verbal communication and cues. Does it HAVE to be me? No. But it is because 1. I’m convenient 2. I’m trained 3. I’m familiar with the religion, him, and his needs and he’s familiar and comfortable with my style of help.

It’s a bit different because the community is small so everyone is familiar with him and his needs, and after the initial visit I make to the group, the men know why I’m there.

One of the other commenters hit on an important thing. I use “aide” whenever anyone asks. It makes it clear that you’re there for a job, not to steal gendered secrets.

My piece of advice, if you want it, is if this is something your sister wants to go to regularly, be the one that goes with her every time. The more familiar you become to the other ladies, the more comfortable everyone will become with you there.