I would think a boarding facility that has private suites might do this. Some facilities have an official policy discouraging it, but we boarded our two dogs together until the older one passed away, even though one weighed 70 pounds and the other weighed 8 pounds (smaller than most cats). The only problem would be that the dog would need more exercise, but I would think they could manage that. As our little guy got older, we boarded our guys at our vet, and they seemed more open to it than “dog resort” places.