I just discovered that my kitten has FeLV. Because this is no longer a death sentence for her, I decided to keep her. She is an indoor cat with no external feline contact, and she is otherwise healthy and happy. But the bias on FeLV is to euthanize around here. It got me thinking, are there places like the old sanatoriums for tuberculosis, consumption, etc., or even leper colonies, but for sick but happy cats or other pets? Where they can live out their lives without being a contagion threat, and with the needed extra care? Anywhere in the world, I ask out of pure interest...
In german speaking countries (Germany, Switzerland, Austria and probably the Netherlands, too) there is the concept of "Gnadenbrot" (literally "bread of mercy"). It stems from medieval times when old people who were too old to work but had worked well in younger times still received payment in the form of bread.
This concept is now applied to farm animals who are too old or ill to work and would usually be slaughtered. These farms are called "Gnadenhof" (farm of mercy) and are usually quite small, ran by environmental or animal rights activists and absolutely dependant on donations. There are extremely few of those farms in Germany.
And there is the fact that animal protection laws in Germany forbid any shelter to kill animals for any other reason than a severe, incurable illness or abnormal behavior that causes suffering for the animal.