Help my sister Tanya Wise with her cataract surger

My name is Diana Lee and my sister Tanya Wise is losing her vision. She needs extensive cataract surgery and her insurance will only pay a portion. She has done all she can trying to get her insurance to cover the entire procedure but they will only cover a portion which will leave her vision very impaired. She is the sole caregiver of her daughter who has severe mental illness along with multiple personality disorder which requires around the clock attention. She needs to see to take care of her.