Good morning: I am sorry to hear about your friends troubles. Could you maybe transport the cats in a well vented but un cooled trailer, like from uhaul or budget. The kind with slat sides and put a tarp over the top for shade. I think with enough water stops the incoming fresh air would allow most of them to make it. I did this while transporting cats from Arizona in the Summer to northern Utah several years ago and it worked out pretty well.