Is it ethical for a student to edit the Wikipedia page of his advisor?
It is not ethical, and is, per Wikipedia guidelines, a conflict of interest.


  If you have a personal connection to a topic or person, you are advised to refrain from editing those articles directly, from adding related advertising links, links to personal websites and similar, and to provide full disclosure of the connection if you comment about the article on talk pages or in other discussions.


There is an exception. For example, let's say Dr. Potato is listed as a life-long sprout, when he is actually a tuber.


  An exception to editing an article about yourself or someone you know is made if the article contains defamation or a serious error that needs to be corrected quickly. If you do make such an edit, follow it up with an email to WP:OTRS, Wikipedia's volunteer response team, or ask for help on WP:BLPN, our noticeboard for articles about living persons.


Other examples of non-controversial edits would be like fixing spelling and grammar errors, or linking to an article on Wikipedia that may be missed.

It is also encouraged that, instead of providing edits and information, you provide:


  Those with a potential conflict of interest are encouraged to upload good-quality digital media files that are appropriately licensed for Wikipedia and that improve our coverage of a subject.


Images and media that are non-controversial can then be used by others to be cited, as they wouldn't express an opinion.

Examples of non-controversial stuff would be like a picture of the person, preferably doing nothing controversial.