I voted for Other Options just because I think it should be judged on an individual basis. There is NO reason to put down a healthy 16 year old cat! Sure the cat is older, but if healthy, let the thing adjust to new surroundings and live out his/her life! I think the two cats in this situation should be kept in a spare room and fostered until a home is found.

I want to have a rescue group someday that caters to geriatric animals. They make perfectly loving pets, and usually have lots of years left in them.