Cathay is a very hard program to earn status, even if regularly flying business class. It probably isn't the right program for him, unless he is eligible for holding and using a Hong Kong Asia Miles credit card, that can give a few perks, and the occasional lounge pass - even without status.

If traveling oneworld there are benefits in having a program based outside of the US (e.g BA) as you'd still get access to a US lounge - but by giving up upgrade perks. There are also some points for economy travel, though with the same risk of low multipliers for economy. BA accounts let you do a household as well, so the whole family can combine their (likely fairly meager) miles, so that you may actually get to use them. Due to the extending use of Avios you could potentially also use a combination of BA, Qatar Airways and Finnair to get the best economy earning (and burning), then moving the accounts between the programs. If going down the BA route there are normally very generous sign-up bonuses for US credit cards that would probably give a fair chunk of miles towards a redemption flight as well.

So, not sending you towards a particular route, but suggesting an alternative