They sometimes communicate with a "Dad Speak" of which the intent that people outside of the relationship (including Hollyhock) wouldn't be able to understand it. However, unbeknownst to the dads, Hollyhock understands what they're saying perfectly well. They live in Wichita, Kansas.
They are mentioned numerous times throughout Season 4 by Hollyhock.
They make their first appearance in Lovin that cali lifestyle!!, when they travel to L.A. after Hollyhock accidentally overdosed on amphetamines, which unbeknownst to anyone at the time was due to Beatrice putting weight loss supplements in her coffee.
They blame BoJack and refuse to ever let him see her again.
In What Time Is It Right Now, BoJack travels to their home in Wichita, Kansas, and after begging them to hear him out, he explains how he discovered he isn’t actually Hollyhock’s biological father—his father Butterscotch is.
He also found out Hollyhock's mother is his family's former maid, Henrietta Platchkey, and he wanted to give Hollyhock her phone number.
They agree to tell her, but still tell BoJack to leave.
They seemed to have allowed Hollyhock and BoJack to talk again, as Hollyhock and BoJack continue to have a long distance sibling relationship afterwards, even visiting him in Ancient History.
- The Language (or "Dads Speak") of Hollyhock's fathers actually consists of adding "ittag" after every first letter in a word (i.e. "What do you guys think?", becomes "wittaghat dittago yittagou gittaguys tittaghink?") the language also doesn't seem to use the word "Is."