First of all, feng shui should conform to people's living habits, and bookcases should be placed behind the sofa. In case the book falls and hits your head, this is called "a gentleman does not stand under a dangerous wall", so it is not recommended from the perspective of living habits. But if the bookcase is strong, it is better to have a distance from where you sit, even if the book falls, it won't hit you.
Secondly, feng shui should be analyzed in detail. The bookcase is sandy indoors, so it should be put in the right place. From the perspective of geomantic omen, it is not necessary to put sand in the sofa. If you let it go, it will be unlucky for Feng Shui. If you need sand there, let it be. In short, it is necessary to analyze the specific house.