Twenty-twelve home page has gone crazy

https://www.diannemonroe.com/wp/

The client has changed her mind several times about what she wants for home page – I had gotten it to a good, two column layout that she liked… in the process making a lot of changes to the child theme style sheets and creating a custom template which I then disabled.

Somehow in all of that the home page is now not working – the left widget column is below the content area, and seems to be in two columns itself. I have spent hours trying to figure out what the problem is, and I am now fearing that I will have to start all over.

Any quick ideas?