Not that bad, when I used to work in a garage im HS doing tires, people would bring in all sort of stuff. I had one of those bubble gum bubble side walls one time, it was all the way around I got to talking or saw something shiny and the thing had bubbled up all the way around, scared the heck out of me.
When tires are run low they eat the side wall, and you get all these little rubber deals inside the tires, never put 2 and 2 together since I was mostly self taught, that was the actuall side wall and it gets paper thin and bad things happen. Not what that is at all.
That front one looks like it could have been run low at some point as well, or it's just curb damage.
Good luck tell them to be careful.