China Visa for American Passport

As you uncle is in Pakistan now, I'm not sure whether he can apply for the entry permit on his own because the embassy there does not accept application from individuals at present. You can tell him to firstly confirm this with the embass before going there to submit the application. If it's true that the embassy doesn't accecpt individual's application, he has to join a tour group organized by authorized travel agencies so as to get the entry permit.