Today, my son took them into the car with him and snuggled with them for about an hour so they could get warm. I really don't want to let them into the house with my four cats, because I know none of them has been given any shots.
After a while, it became apparent that they didn't want to go home, so Dan made them a little box with an old afghan so they could snuggle in there. After a while, the Mother Cat came and snuggled in the box with them. She's not much bigger than they are! They've been there for several hours now - all three of them.