Anyone had to deal with caring for an elderly relative?

My wifes grandmother is 96 and her father has cancer and will be lucky to make it another couple years. Her mother has indicated that she will not be helping and I would not want her to either. I suspect that the money for her care facility is likely about to run out and she is still healthy as a horse but mentally unable to care for herself. I simply cannot afford the $5,000/month it costs for her care facility and her other brothers and sister cannot either. I don’t have all the details yet but my wife is a little nervous which leads me to believe this is about to be an issue for us since she’ll be reponsible for her if her dad passes away. If any of you have dealt with something like this I’d like to know how you have resolved it.