I'd feel very uncomfortable about that, although I understand why your dp would feel like ignoring it. It's tricky to solve and it would feel like he was dredging up the past - out of sight out of mind type of thing.
But, it's important. If he leaves the situation as it is, he's basically relying on his wife to behave in an ethical manner and to be gracious enough not to cause problems in the future. And I don't think he has any grounds for trusting her to put his and your best interests before her own? After all he didn't anticipate she would refuse to move with him, or that she would refuse to deal with the divorce when he's tried previously. No precedent for trusting her with such power over his life and his families lives.
Even just writing this, it feels incorrect, as she is his wife, and it's not the case she's a 'stbxw' (soon to be ex wife), or an ex at all really. Even our language isn't set up for a this type of situation!
So, although it's difficult and easier not to think about it, he needs to get himself legally disconnected from his wife. I'd suggest finding and employing a representative in China rather than going himself.
It's very easy to get lost in the bureaucracy if you don't speak the language, have experience of the processes, and also, if she makes it clear she doesn't want a divorce to happen, and finds a sympathetic audience, you may find it somehow just gets stuck in red tape forever. More chances of success with someone who can navigate of this stuff.
Good luck for you, and your dp.