Need to replace software

A friend of mine has problems with a website. This is the website: http://www.aasacramento.org/meeting-schedule

I think the problem is that the webmaster is no longer working on this and they don’t have anybody that can make changes to the code. I’d like to replace this software with something that is opensource.

I want anybody in the office to be able to update the schedules without having to use any coding.

Any help is welcome