Should I put my dog to sleep?

My dog Cuddles was Diagnosed by a vet that she had a serious infection in her uterus and would not last 2 more days. The operation costs 2,000 and i can not afford to pay that. I recently lost my job and this is my mortgage payment for one month. I tried go fund me, but it has been unsuccessful, and no one has funded me yet and it has been 5 days. I love cuddles so very much and i have had her and her brother for 9 years now. The best i could do for her was antibiotics. In the past couple days, she has started to walk again and eat, and i thought things were going better. But, when i woke up this morning, she was blind. I found this out because when i pet her, she looks around the room, and when she walks, she only walks in circles and runs into walls. However, one day when cuddles was staying at our friends house for a little while, Red (cuddles' brother) was whining uncontrollably and would not fall asleep. I know you cant put a healthy dog down, But the thought of Red being so sad without cuddles makes me cry. They were rescues and we got them when they were about 6 -7 years old (they didn't know the exact age) And now Cuddles is 15-16 yrs. And so is Red. I really don't want to put her down, But i already scheduled an appointment already for a week from today. I told them if she gets better from now till then, I would cancel.
If she gets better, but still cant see, is there anything out there that will help her with her blindness(?)? She is also deaf,
Added (1). And i am thinking she cant smell because when i put food in front of her, she wont sniff it. And i also tried to warm up some chicken soup broth because i know it has a lot of smell, but she wont sniff that either. She was recovering yesterday, and i would HATE to put her down just because she is blind.

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