Themes update causes admin to go blank

My client updated only the themes in a site using 4.2. Everything was fine, she didn’t update the plugins, tho some needed it, just the themes (all the twentyxx themes, from 2011 to 2015.) The theme in use is the child of twentyeleven.

As soon as she updated the themes, the admin was reduced to only the left hand navigation column, the top bar and main sections are both white. The website shows just fine, although the top bar doesn’t show when logged into the admin.

The site is https://hominyridge.com/

I’ve tried renaming the plugins folder. Also deleted all but the 2011, 2011-child and 2012 & 2014 themes, renamed the 2011 & child folders. None of these brought the admin back.

Any suggestions?