Yes, ‘his’ is indeed a pronoun. Specifically, it is a possessive pronoun used to indicate ownership or association with a male individual. For instance, in the sentence ‘This is his book,’ the word ‘his’ shows that the book belongs to him.
Possessive pronouns like ‘his’ are used to replace nouns and show possession without having to repeat the noun again. ‘His’ functions differently from other types of pronouns, such as personal pronouns (e.g., ‘he,’ ‘him’) that refer to someone directly or demonstrative pronouns (e.g., ‘this,’ ‘that’) that point to specific things.