Why is the preposition "from" necessary here?
Good question. Remember that "from" as a preposition is used whenever we are talking about origins, sources, and starting points. In the case of this clip, it is being used to let us know the "source" or what the mother is reading. If we were to omit the preposition the sentence would need to be rearranged in order to be grammatically correct. Ex: I’m from the U.S. Ex: This scene is from an old movie. Ex: I borrowed a book from the library. Ex: I heard from my brother.