I have probably taught dozens of chinese students many years ago... perhaps even some of these captains.
The would come over the the states 50 at a time, and divided into two groups, those that could speak english well enough to begin flight training, and those who needed remedial english courses first.
They were all bright, pleasant, and motivated young men... however some struggled for other reasons. Many you could tell were just not passionate about flying. If you could get them to talk candidly, they would say they signed on for the training because it would give them a good salary back in china. Or their parents talked them into it.
Many were downright afraid to fly. For most, the first plane they have been on was the one that flew them to the US for training. While I was building flight time for a shot at a turboprop in the regionals, they were going straight into 320 and 737 jobs, and many would become captains in a few years.
The downside is that they are bonded forever, almost no chance at all to change airlines. The other side is that they had their training pay and went right to the big iron with no dues paying. You can see both sides of that arrangement.