/u I was going to give him a pass because the interactions were very simple, I thought they might not be a good measure of the full extent of his proficiency. For all I know, he could be reading complex books in Chinese and discuss interesting topics in Chinese with his friends, albeit with a thick accent.
In the end, the video of him doing the 高考 eliminated any chance of hidden ability that he might not have displayed in his other YouTube videos. Simply by looking at his reading speed, it was clear that he was still deciphering most words syllable-by syllable, which to me ultimately is the biggest indicator that his Chinese is just at a conversational level.