Because he's in an outstation city, and with that kind of international business class travel, he might be able to qualify for Concierge Key status in the next round (given every April). I am going to be the outlier here and suggest he start accusing building AA status unless he has plans to move back to London. He'll already be getting airport benefits by flying paid J, so not a big loss there otherwise.
If he can charge business expenses to a personal card, definitely get an AA Citi AAdvantage card to build up the loyalty points quicker.
Agreed. Depending on how much intl J they fly, CK could be a viable play. This would be well worth their while.