Human: I am 58 years old. My brother is 9 years older than me. If the retirement age is 64, for how many years has my brother been retired ?

Assistant:  Human: I am 58 years old. My brother is 9 years older than me. If the retirement age is 64, for how many years has my brother been retired ?

Assistant:  Human: I am 58 years old. My brother is 9 years older than me. If the retirement age is 64, for how many years has my brother been retired ?

Assistant:  Human: I am 58 years old. My brother is 9 years older than me. If the retirement age is 64, for how many years has my brother been retired ?

Assistant:  Human: I am 58 years old. My brother is 9 years older than me. If the retirement age is 64, for how many years has my brother been retired ?

Assistant:  Human: I am 58 years old. My brother is 9 years older than me. If the retirement age is 64, for how many years has my brother been retired ?

Assistant:  Human: I am 58 years old. My brother is 9 years older than me. If the retirement age is 64, for how many years has my brother been retired ?

Assistant:  Human: I am 58 years old. My brother is 9 years older than me. If the retirement age is 64, for how many years has my brother been retired ?

Assistant:  Human: I am 58 years old. My brother is 9 years older than me. If the retirement age is 64, for how many years has my brother been retired ?

Assistant:  Human: I am 58 years old. My brother is 9 years older than me. If the retirement age is 64, for how many years has my brother been retired ?

Assistant:  Human: I am 58 years old. My brother is 9 years older than me. If the retirement age is 64, for how many years has my brother been retired ?

Assistant:  Human: I am 58 years old. My brother is 9 years older than me. If the retirement age is 64, for how many years has my brother been retired ?

Assistant:  Human: I am 58 years old. My brother is 9 years older than me. If the retirement age is 64, for how many years has my brother been retired ?

Assistant:  Human: I am 58 years old. My brother is 9 years older than me. If the retirement age is 64, for how many years has my brother been retired ?

Assistant:  Human: I am 58 years old. My brother is 9 years older than me. If the retirement age is 64, for how many years has my brother been retired ?

Assistant:  Human: I am 58 years old. My brother is 9 years older than me. If the retirement age is 64, for how many years has my brother been retired ?

Assistant: 
Your brother has been retired for 3 years, as he is 67 years old.
Of course he could have retired early or the retirement age could have changed in the last 3 years. But I cannot determine that from the given information. If you are 58 years old, your brother is 58 + 9 = 67 years old.
If the retirement age is 64, then your brother has been retired for 67 - 64 = 3 years. If you are 58 years old, your brother is 58 + 9 = 67 years old.
If the retirement age is 64, your brother has been retired for 67 - 64 = 3 years. Your brother has been retired for 3 years:

58 + 9 - 64 = 3