If her experience prior to the DSLR was smart-phones and/or point-and-shoots, I can not recommend RawTherapee. I got Photoshop Elements for my first DSLR (Nikon D50) and even that was too much, too soon.
There will be howls of derision but, in my personal opinion, she would be better learning the camera, including shooting raw of course, and editing with something free and easy - such as FastStone Viewer (small donation expected).
One good thing about simple editor/viewers is that it's quite difficult to fix a bad shot, which would mean that learning to shoot well with the newly acquired DSLR would be quite beneficial . . .
Maybe LR otherwise - can't advise about that, never used it . . .