My grandma is 89 years old, and she forgot about her AAdvantage account. While visiting, I logged on to see how many miles she had, as we have helped her book flights for her sister from NJ to come visit. 0 miles. Through a credit card signup bonus and additional spending, she accrued over 85,000 miles. Now, zilch.

What is the math on the miles? Would it be worth spending $400 to re-instate 75,000 of those miles? I'm fairly certain it's not worth $600, as it's only 10,000 miles more. If so, I will keep a much closer eye on her account. Thank you for your time.