Thanks for all the replies so far.

Interestingly, only Expedia sells the itinerary with transit at ZRH. If I use CX's website, then it only shows itineraries via FRA. Not sure if this means that CX doesn't want me to fly via ZRH.

If he misses his CX HK-bound flight, then there are three nonstop options: Korean, Asiana, and LH. None of these are in One World. Out of the three, he only likes LH. Korean is a no-no, due to its horrible reputation in both safety and management.

Another option is flying Finnair, but the fare is more than US$1+k more.