Sidebar disappeared after upgrade to 2.9.1

Hello all of you lovely people. A friend of mine upgraded their wordpress installation yesterday, and since that time the sidebar has disappeared from the main page as well as on single post pages. The sidebar does show up on single static pages (i.e. “about”).

I’m guessing that something either broke in the theme with this new upgrade or something else. Looking at the rendered page’s source, it appears as if the sidebar is actually there, but it’s not being displayed anywhere on the page.

Could someone help me shed some light on this problem?

The site is thehealthyirishman.com

Thanks 🙂