If I was closer, I’d be tempted to anonymously visit and say mean things to them. I can be a devious asshole when it is warranted… “It’s your fault he is sick because you sheltered him too much when he was young, so his immune system was not prepared to fight off everyday germs.” comes to mind. Might not be 100% true, but neither is it true that it is your fault.
But seriously… Sorry you’re going through a difficult time, @Nabiki. I hope the situation is resolved before you are scheduled to go on your trip, for better or for worse.