<s>[INST] 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 ? [/INST] 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. </s>