Eh? I'm not sure where you got that idea.
In general, Esperanto is not pro-drop, but it doesn't usually do "dummy subjects".
So you have "pluvas" because there is no object that is raining, and "estas multaj bestoj tie" because you don't need the "there" that English has in "there are..." sentences.
But you wouldn't usually say "estas de mia patro" when talking about a book, I think, but "ĝi estas de mia patro".