Maybe they could take everything from him and there wouldn't be a heck of a lot Elon could do about it but why would they. Look at how high profile he and his company is, China would just be shooting themselves in the foot, they want foreign investment, preferably joint ventures so they have easier access to new technology but Elon managed to be the first company to set up there without a joint venture with a Chinese partner. That was a very smart move because it is much harder and more obvious for China to "borrow" Tesla's tech although it certainly won't stop them from trying
