Your big mistake....JMO...people share too much. Where you posting in a disability section on Reddit? If not why mention your daughters disability? Lots of people are interested in cool auto stuff. Auto parking. Adaptive cruise control. Back up cameras.
I think, without any evidence to support it, factory stuff is more reliable then cameras and other stuff installed aftermarket. Without a doubt easier to fix, any car dealer can fix it. Some of the stuff installed by shops are sketchy.
All of the instructions tell us not to rely exclusively on camera and other aids. At a minimum walk around the car so your daughter knows exactly what shows up on the camera and if there are any blind spots.
There is no issue if a disabled person needs hand controls to drive is allowed to drive. I have no idea if a driver that has to rely exclusively on backup cameras, which are not designed to be used exclusively, is allowed to drive under state driving qualifications. Your case would be stronger if the camera allowed your daughter to drive easier but when necessary she could use mirrors or turn around, possibly with pain.