We put all the girls inside already, put up the screen barricade between the two sides and I'm fogging that entire laying flock with oxine, just in case anyone else is having an issue. We also put Georgie and Caroline back in there to enjoy the clean air bath. Isaac is in the original 8x8 side where he usually roosts, just alone, but he can see them just fine. Not sure what tomorrow will hold, but one way or another, he will be back with his girls. The next few days should be cooler and less humid so maybe that will help everyone.
ETA: If Isaac passes away and I still have his son, Ranger, I think I may just put Ranger in the main laying flock and leave Rex, my BR, where he is, separate with his own girls for the time being. I don't care about getting fertile eggs from the main flock anyway, so doesn't matter if their rooster is a mixed breed. He can alarm as well as his father can-if he's half the rooster Isaac is, he'll be awesome. If I do that, I may also move Nugget back into the laying flock with Ranger, since she raised him.