Why would a 5 year old Chrysler 300 with less than 30,000 miles on it just stop working?

So my mom and brother left Pennsylvania today to come visit me in Colorado, and they were driving my grandmas Chrysler 300…she bought it new and didn’t use it much, so it has somewhere around 30,000 miles on it, but less. Never been in an accident, never had any problem….they had driven for 3 hours and were pulling off to go to a rest stop and it just stopped and wouldn’t do anything. They had to push it into a spot. Is that not insane? This just happened a few minutes ago and we all feel like there’s no way the transmission blew on this car or anything major because it’s hardly been used! Does anybody know anything about cars and might be able to suggest something they should do? It’s redonkulous, and to make an extremely long story short, it’s pretty important that they make it out here and don’t have to go back home…...