Perhaps you guys that deal with ITAR and EAR can correct me on this and/or update this.
My understanding is that beyond the whole foreign national thing, China and Iran are special cases. These two countries are total no-goes for training and weapons sales. Circa 2014, exceptions for "basic maintenance" of weapons, as opposed to training in the use of the weapon were proposed, but I have no idea where that went. Nevertheless, it was conveyed to me that NO approvals would ever be given by USG for China and Iran because they were in some special category separate from run-of-the-mill countries, possibly involving ongoing arms embargoes.
So regardless of whether this kid was PLA or not, mere Chinese citizenship is going to cause problems for someone now that this is on the public radar screen.
I was briefly involved in a plan to provide training to the Hong Kong Police Force and that was derailed based on some timely legal advice to this effect.
As an aside, IIRC Pat Rogers had a pretty upfront statement on his website that he didn't train foreign nationals under any circumstances. I never knew him, but I seem to recall that being on his website. Perhaps he just thought the juice wasn't worth the squeeze in this area.
A lot of trainers have no idea of the perils of training foreign nationals.
ETA: for those of you with expertise in this area, does martial arts training fall under ITAR?