I didn't mean to scare you. If the myFICO simulator said he needed new credit, then that is probably true.
By reaging, I am referring to average age of accounts, which is a component in FICO scoring. The longer one's average age of accounts, the better (all else equal).
Utilization
Before getting the new card, his utilization is 10%. That's actually very good, although not quite ideal. (1-9% is best.)
Once the new card reports, his utilization will be 2%. Going from 10% util to 2% should be worth a nice little boost.
Average age
Before the new card, his average age was 2 years. (3 years on one account + 1 year on another account) / 2 accounts = 2 years
When the new card reports, his average age will be 1 year and 4 months. (3 years + 1 year + 0 years) / 3 accounts = 1 year and 4 months
Going from 2 years average age to an average age of 1 year and 4 months will cost a few points.
The inquiry to get the new card may have also cost a few points on the report where the inquiry was pulled.
What I was getting at in my post above is that the overall effect of opening a new credit card account will depend on whether the benefit from the improved utilization outweighs the damage from the decrease in average age and the inquiry.
(The average age calculation I did above assumes that these two credit cards are the only accounts on his reports. If he has other accounts, whether open or closed, the ages of those accounts would need to be part of the calculation as well.)
Make sense?