I'm guessing the patients were required beforehand to sign forms consenting to the device being taken out in the event of ___________ (in this case, the company going under). Because otherwise I don't understand how it'd be legal to force someone to have brain surgery against their will.
But if the company can't continue maintenance and support for the device, why not have her sign new forms exempting them from liability and just let her keep it? Is potential liability not the only limiting factor here? And would this be ethical?
Even if her death is guaranteed by leaving it in (and I'm not sure it is without more information), does that make it ethical to remove? Perhaps the patient would prefer a shorter life with greater quality in regards to her seizures. After all, don't we allow and accept cancer patients to forgo treatment and enjoy the time they have left?