Mrs. Maisel's father was a Columbia professor. Especially in season 1, he doesn't seem to have an income outside of a professor's salary. He lives in a "classic six" on the upper west side and have full time live in help, which would be utterly out of the price range for a Columbia math professor today.
For context for people who haven't seen the show, the family lives in an apartment that would go for about $9 million today, and goes on fancy, multi-month long vacations.
Spoiler for the show, but they did clarify in Season 3: >!The apartment was owned by Columbia University and was granted to Professor Weidman. Also, the full-time nanny was subsidized by his wife's trust fund money (funded by her oil money family).!<