He hasn't tried to reenroll, because he was unable to find an advisor in the same department. Taking an advisor from a different department would mean to start over on his thesis. I'm not sure what would have happened if he was still enrolled in this case. It seems to me that no one can force an adviser to work with him, so this talk about enrollment is a moot point.

Also, according the professor, the only Chinese pressure was an email from a Chinese foreign student in Canada who felt offended by the cartoon. It seems like the initial email from the professor was just not worded carefully and had some speculations about visa repercussions and that is what the entire article is based on.