Best solution here would appear to be never sync that iPad again, back it up to iTunes, disable its Wi-Fi, and consider it her speech appliance. Don't update the OS, don't sync to iTunes, never do anything with it again aside from using it for this essential purpose. If you have to buy another one, restore it from your iTunes backup. These are the 'legal' avenues, clearly with jailbreaking it's simpler.
Unfortunate that a legal battle puts you in that position, but if this app is as important to her life as she says, she should be perfectly fine freezing that iPad where it is and not treating it like an iPad any more. It is now a dedicated appliance, not a general-purpose iPad. Buy another one for everything else.
Sucks, but, best solution given the circumstances, I think. Obviously, it'd be great if the circumstances changed.
(Edited to add backup.)
Unfortunate that a legal battle puts you in that position, but if this app is as important to her life as she says, she should be perfectly fine freezing that iPad where it is and not treating it like an iPad any more. It is now a dedicated appliance, not a general-purpose iPad. Buy another one for everything else.
Sucks, but, best solution given the circumstances, I think. Obviously, it'd be great if the circumstances changed.
(Edited to add backup.)