In this sentence, the correct word to fill in the blank is "detail." So the sentence should read:
"My father helped me to review my work. He always says that we need to pay attention to every detail."
Explanation:
"Detail" fits the context because it refers to the small parts or aspects of something that require careful attention.
"Situation" does not fit here, as it refers to a set of circumstances or a specific state of affairs, which does not match the context of reviewing work.