We were on the same cruise as your parents. It was a trip through hell...and we were one of the lucky ones, managing to get out of Mexico on the first day. Even then, it was a day of confusion, no help from the cruise lines, very little Celebrity representation at the Acapulco airport.
I observed two things from all this.
#1-there was an apparent engine problem almost from the time we left Fort Lauderdale. We understood that representatives from the ships engine manufacturers were flown to meet the ship in Aruba to investigate an apparent problem..and that was only three days out of port. Several other guests said they were receiving e-mail from home stating that family members knew there was a problem with the boat at least a week before we were informed of anything.
#2-Celebrity really needs to work on their internal communications. If they had a 'crisis plan' to deal with this type of problems (and I'm sure they did), they had a real difficulty implementing it. Nobody on the shore teams really knew what was going on, or where to send the guests. There were lots of people who simply fell through the cracks and were not assigned flights home or hotel rooms for the night. I don't understand how that could happen when you have a manifest of everyone on board. Even when we were flown into San Diego it was apparent that nobody there could answer any of our questions. We were simply advised to call a 1-800 number the next day to try and sort through our travel plans home. But this is the best part... In making these calls to their home office, the first THREE people we talked to didn't even know the ships passengers had been put off in Acapulco, or there was a problem with the INFINITY.
Others can say what they want about getting flights out of places like Mexico, and I agree it would be difficult. But it seems Celebrity's final decision to cancel the rest of the cruise was a 'snap decision', with little planning or foresight into the difficulties of what the final outcome would be.