Concept:
"Neither" is a singular subject and takes a singular verb. Proper subject-verb agreement is essential for grammatical correctness.
Step 1: Identify the subject.
The subject is "Neither of the two brothers".
Step 2: Determine the correct verb form.
Since "Neither" is singular, it should take a singular verb "is", not "are".
Step 3: Locate the error.
The phrase "are ready" is incorrect and should be replaced with "is ready".
Correct Sentence:
"Neither of the two brothers is ready to go."