If you buy a "normal" AT&T Global Phone Card, the card will charge him civilian rates.
Instead, you can buy him a special discounted AT&T Global Phone Card through
AAFES that will charge him a lower per-minute rate.
The rates are still crazy. The charges on a 550 minute card are $.21/minute for calls from Iraq to the U.S. It's best if he call home, hang up, and let you call him back. Phone calls from the U.S. to Iraq can be made for as little as $.04/minute.