The rules for pronoun references are not hard and fast, as this page from Furman University explains:
MUDDY PRONOUN REFERENCES: these are the situations which create
comical or very confusing sentences because your reader is not sure
which noun the pronoun is supposed to refer to.....
There is no set rule to solve this problem in every unique situation,
but remember the following: Your reader will usually try to connect a
pronoun with the noun or pronoun that is the subject of the previous
clause or sentence and which most logically fits with it in gender.
This Towson University page takes a slightly different approach, claiming that there is an rule which would be to have every pronoun preceded by a clear noun antecedent.
A pronoun should refer clearly to one, clear, unmistakable noun coming
before the pronoun. This noun is called the pronoun’s antecedent.
Unfortunately, it is very easy to create a sentence that uses a
pronoun WITHOUT a clear, unmistakable noun antecedent.....Such errors,
called FAULTY or VAGUE PRONOUN REFERENCE, can confuse readers and
obscure the intended meaning."
My personal opinion is that many schools tend to become very dogmatic and shift something that is usually preferable into the rule category. I believe the Towson source oversimplifies the issue and actually that
A pronoun usually refers to something earlier in the text (its
but not always. For instance this source from University of Pennsylvania admits:
There are a small number of cases in which it is OK to use a pronoun
with no antecedent. Words called expletives serve as dummy subjects
(or, referent-less pronouns). Standard English has two expletives: it
and there. There are two kinds of dummy it: impersonal it and
anticipatory it. Impersonal it is the it that you find in weather
phrases and such places. You can't figure out what it means, and yet
there is no other grammatical way to say the sentence. With
anticipatory it, there is usually a clause that could serve as the
subject of the sentence if the sentence were rewritten without it.
Your Assumptions: You did not show the sentence preceding the one you quoted, but as the Furman source notes, a pronoun in a following sentence might refer to a proper noun in a previous sentence. I suggest that is more likely the case than your idea that Obviously the author intends us to understand 'he' as referring to the parenthetical use of the proper noun 'Chief Brody'.
Your Question 1: There is nothing that would preclude the noun being in a parenthesis, but my bet is that it the previous sentence refers to Chief Brody explicitly and that is where the noun reference for this pronoun is found.
Your Question 1 (Part II): As the U. Penn source notes there are anticipatory referents for pronouns that occur in English. However, again, I suspect the previous sentence already establishes the referent Chief Brody so in this case there probably is a traditional antecedent that would be clear if we saw the prior sentence. But taking a purely theoretical approach it is always possible to include information in parenthesis to clarify a noun our pronoun, called an appositive.
Parentheses can be used.....As an appositive. An appositive is a noun,
pronoun, or noun phrase that identifies or explains another noun or
pronoun before or after it.
Your Question 2: I think the U. Penn site gets into the deeper understanding of the rules that you are seeking. See Your Pedagogical question: below.
Your Meta-question 1: probably yes - I'd have to see the preceding sentence or sentences to be certain.
Your Meta-question 2: Use of clarifying information in parenthesis tends to be highly flexible in English. Certainly using the parenthesis to cause an anticipatory referent to exist, such as an appositive, is allowable. The main question is can the reader clearly identify the referent of the pronoun? Generally the reader will look for an antecedent, but a clear referent in parenthesis following the pronoun would work in many instances, too.
Parentheses are most commonly used to enclose an explanation or
afterthought which relates to the main message of the sentence. The
use of parentheses is often a judgment call.
Your Pedagogical question: I would suggest:
- Your reader will usually try to connect a pronoun with the noun or pronoun that is the subject of the previous clause or sentence and which most logically fits with it in gender.
- There are a small number of cases in which it is OK to use a pronoun with no antecedent, such as the impersonal use of it or there in a sentence like It is raining.
- There are a small number of cases in which it is OK to use a pronoun with anticipatory referents (still referred to as an antecedent but actually following the pronoun) if the referent is clear, such as the anticipatory use of it in the sentence It is clear that Al's beard is a mistake.
- It is always possible to clarify a pronoun by using an appositive, which is a noun, pronoun, or noun phrase that identifies or explains another noun or pronoun before or after it, and the appositive is usually set off with either commas or parenthesis.