Thank you, everyone, for all the lovely comments!
My sister’s bag never arrived. Aerlingus never called her, nothing. I recommended she go to the airport very early today before her flight home, find the friendliest face at their counter, and tell her tale in the sweetest, saddest possible way so she can get some help. She can always ramp up the anger later if she gets no meaningful assistance, but if you can get an advocate from the start, it seems you have a better chance of someone taking extra effort to help you. I’m crossing my fingers she will at least get her luggage on the return trip home. She had a great time in London otherwise!
