Oh Sally your blood pressurew must have gne through the roof today ..I hope you will now try to relax, not worry about next week but just chill out.
Of course to FIL the world is tumbling down around his ears. He is in a nursing hme, but until now had the illusion that his wife was safe at home with you and your family, and would be for the rest of her life, which will probably be longer than his.
Now, he is confronted with the total cancellation of his plan. She will not go home again; you wil leave, he will have to sell the house to finance his own and his wife's nursing homes. I understand he is in a panic.
BUT ...YOU have been putting up with impossible conditions for more than a year and you cannot and will not do it any longer! So even though it forces all his plans to change, it is happening and there is no way to stop it. Let BIL rant and rave, but you are off the hook.
What a sad situation for everyone .. neither of them wanted to get sick. I don't know how you put up with it this long, but go now, and enjoy the rest of your life in peace and happiness. You have earned enough points to last a lifetime ...