I'm confused about why anyone would bring their females in heat to a home with an intact male, and one that is related to them
A few years ago when my 3lb little one came into heat, (even though I kept them apart) I was so worried my little male might have still got to her (her daddy) that she went right to the vet and was spayed, no problem at all. I wasn't about to take any chances on one that tiny having pups. I would think an emergency spay could still be done before she gets much further along.