You can do that with Virtual Desktop. Most, if not all, of the 2d content viewing apps in VR present a 2d screen represented within a 3d space. For example, Netflix has you sitting on a couch in front of a simulated large screen. Another app might have you in a movie theatre.
However, these apps also allow you to display the 2d screen in a void, with no surrounding space. You can freely grab the 2d screen and make it much, much bigger, so it fills far more of the visual field than in the simulated room version. And, you can grab the 2d screen and move it around, so you can look at different parts of it. You can choose to display it flat, or fish-eye.
At any rate, understand that it *has* to display the 2d screen in a 3d virtual space. If it just sends the 2d image to each eye like a tiny monitor, full-frame, your eyes don't know what to do with it. Now, that said, there are video players which will allow you to force this configuration - it's used for playing pre-processed 180/360 video.
If what you want is a really big screen that someone can look at as if they are holding it up to their face, so to speak...it should provide that.
You can also create custom
$1 for VR desktop, and it might be useful for this purpose.
Above all, unless you're up for owning a vr headset anyway, you should have her try one on first, to see how well she can see the content...it may be a moot point whether vr desktop works or not. Best of luck.