After all, people are not just your own place, but everyone's environment. If you are not satisfied with her behavior, I think you should try your best to help her read more books. You can talk to her. Are there any interesting places in these books? Or try to cultivate her interest in this way.

Every time she buys a book, you can read it, and you will get something. The more books you read, the better it will be for people, so trying to feel such resources will occasionally benefit you.

However, if your daily life is affected by her too many books, for example, she throws books everywhere in this room, often littering and complaining that she can't find them, then you can talk to her.

For example, you can discuss where the book should be put, and two people can discuss whether her book can not affect your daily life. In fact, it is helpful for her and you to cultivate better living habits.

If nothing I say can help you, it's time for you to reflect on yourself deeply.

Why do you dislike her buying books? Does it mean that she hates him for buying a lot of books and doesn't read them, or does it mean that she wants to read books, but she actually avoids reading books in another way.

In fact, this is an opportunity for you to know yourself.

In my opinion, no matter how many books my parents buy, I won't feel any problem, because I think this is his own business, and he has the right to decide his own life, which has nothing to do with me.