His fiancee, I believe, has never really thought for herself. This is common amongst JWs. The poor thing... she must be devastated. The JWs who actually study and are familiar with the Jewish calendar know of the discrepency. Their excuse is that they use a pre-exilic calendar, but it's true that even regular calendars list the Passover. At least mine do. It's one of those things JWs just go along with like whatever.
I feel jealous that she got invited to a Passover Seder. I tried to invite myself over but it didn't work lol. There aren't a lot of Jewish families where I live but my son and I love learning about the Jewish culture. It's one of the things I miss about NY. I only know 1 family and she was nice enough to give me some extra dreidals for Hannukkah.
Also, I love The Marvelous Mrs. Maisel!!!