My mother in law has a cat, Sweet Pea, that is in the end stages of congestive heart failure. There is one last trip to be made to the vet and a flurry of good byes. It will be soon.
Sweet Pea was an older cat that had been in the shelter for several months, and even with the waived adoption fee, apparently no one seemed to notice the small gray and white cat waiting patiently for someone to love. Her fate was grim until my mother in law noticed her and brought her home.
My mother in law saved Sweet Pea’s life and Sweet Pea returned the favor by helping to lead my mother in law out of the darkness of the recent loss of her husband of 60 years.
She is upset about this turn of events, but she understands it is the kindest act left in a long list of kind acts between the two of them.
Random thoughts 
This story just touched my heart. My condolences to you about your father in law. My heart just breaks for Sweet Pea and your mother in law. It seems like they were put together in each others lives at the right time. It’s always hard to say goodbye.