I am very sorry to hear about Ginger's turn for the worse.
Not that it matters but you refer to Ginger as him and her so I'm not sure whether your kitty is male or female, I apologize if I am referring to the wrong sex.
Did your veterinarian give you a possible diagnosis for Ginger's sudden blindness?
Were any sort of diagnostic tests done?
Has she had any weight loss?
Any increase or decrease in food or water consumption?
Does she go outdoors?
Any possible exposure to toxins?
If no testing has been done bloodwork including a feline leukemia and feline immunodeficiency test, complete blood count, biochemistry profile, T-4 to evaluate thyroid function should be done as well as a urinalysis and blood pressure test.
Sudden blindness can be due to metabolic organ failure which causes increased levels of waste product build-up which affect brain function, high thyroid hormone levels which can lead to hypertension and bleeding in the retina or retinal detachment, toxin exposure affecting the brain or organs, parasites (like toxoplasmosis) affecting the eyes and brain function, viral, fungal or bacterial infections, or even a tumor in the brain. These disease processes can all also affect brain function and so would make sense as far as her change in mental status now.
Unfortunately Ginger is beyond home care at this point, other then confining her so she doesn't hurt herself and trying to make sure she continues to eat and drink or forcing liquids and food if she isn't eating. She absolutely needs a veterinary examination and diagnostic testing. Please let me know if you have any further questions.