The WeChat account already been banned. http://www.xinhuanet.com/fortune/2018-12/05/c_1123807970.htm
Now it's time for the police to dig out the real criminal.
A proxy/jumper account might work until (as you said) somebody starting to cash the money out.
Seems a very dumb thief, but again, how do somebody steal money online without been caught now days?
LOL
BUT, I almost feel pity for him. Take look the picture of him on the news[0], look the environment he's living in and how thin he is, pretty rough life I'd say.
I hope hes doing well in prison and become a better man after this. If he can write a virus capable of doing all that, then I think he will also doing well in most companies that does web related works.
Plus, I have read a news article on Wired[0], I don't think Monero is private enough to against state/police launched attacks?
Consider there are many ways to make money legally, doing something at that level of risk maybe just not worth the trouble.