Could he try to bring her back out into the coop for the daytime? She can still be in a wire dog crate with her own food and water. If he can let her be with the others during the day, she might eat better. If she refused scrambled soft egg, watery chicken feed, she might like a little canned cat food or tuna. If her crop is not emptying overnight, she may have a crop impaction or sour crop. Can he use a phone camera for pictures of her or her droppings? If not passing droppings, it might help to give a human calcium tablet or Tums, in case she is having trouble passing an egg or a lash egg. It sounds like she may have a reproductive disorder, possibly salpingitis or egg yolk peritonitis, or water belly. Most of the time we won’t know what until a necropsy can be done after death unfortunately. I do home necropsies on any I lose, and I have learned a lot about what can go wrong with my birds.
I'm sorry you and your family are going through all this! It's difficult when you feel you need to be in two places at the same time. All you can do is the best you can do. I hope everything works out okay. 
