* Grammatically: "Those" is a demonstrative adjective and pronoun and does not change based on person. It's neither first, second, nor third person.
* In relation to a subject: If you are referring to something already mentioned, "those" can be used to refer to a third person subject.
Examples:
* "The apples are red. Those are green." Here, "those" refers to the apples that are green, which are not the speaker or listener (third person).
* "I saw those birds flying in the sky." "Those" refers to the birds, which are not the speaker (first person).
In short, "those" itself is not third person, but it can be used to refer to a third person subject.