My views on cats living outside totally depends on the cat (age, reason for living outside etc) and what their outdoor accomodation is.
What is the cats outdoor accomodation like? Is the owner of the 2 cats spending plenty of time outside with the cats giving them cuddles, grooming them etc?
My stud boy lives outside due to the fact he hoses everything with spray however he has a 2 storey cat house with lighting that has got his toilet and kitchen facilities downstairs and his bedroom/play area upstairs with a 10x8ft run attached to it so he can choose whether he wants to sit outside or play on his cat playstations in a snow blizzard or whether he wants to lounge around in his house if it's tipping with rain. My cats don't need it due to their breed but most people with other breeds, particularly shorthairs, also have heating in their cat houses for when it is cold so that the cat stays nice and warm.
I also make sure that I spent time outside with my boy every day come pouring rain, sunshine, blizzards or gale force winds cuddling him, playing with him etc and for when I'm not out with him if he doesn't have a girl in with him for company he has got a radio to listen to (he's a radio 1 fan!) and our next door neighbour always has a quick chat to him when she's going in and out of her bck door lol.