It looks like the problem is that every time she is creating content she is choosing the wrong option.
In the Wordpress back-end if you click 'Write' you get a choice of 'Write Post' or 'Write Page'- it looks like she is choosing 'Write Page'. Every time she creates a new page, it'll get added to the 'Pages' menu- thus increasing its size.
She should use the 'Write Post' option for general updates (i.e. blog-type entries) that get less relevant as time goes on, and 'Write Page' for important pages (i.e. content) that should be accessable from the homepage at all times.