Although she never states that she does not like her brother, the author infers in her book that they did not have a good relationship.
This sentence contains an error in diction. “Infer” has been used in place of “imply.”
“Infer” means “to draw a conclusion based on given information.”
“Imply” means “to indicate without making a direct statement.”
Readers and listeners — people who receive information — infer and make inferences.
Writers and speakers — people who give information — imply and make implications.
In the sample sentence, an author is said to infer something in her writing. This is incorrect. An author implies something in her writing; readers infer something from what they read.
Although she never states that she does not like her brother, the author implies in her book that they did not have a good relationship.