How to teach a teenager fixated with liberal spending that when you buy on credit its NOT your money!?

He should have been shown when he was a kid how much money the family had coming in each money, where that money must go, and how much remains. The parents should let the kid fail on his own or they will have to bail out this kid that feels entitled to everything he wants. My guess is the parents bought him up buying him everything he wanted and he never had to work and learned the value of a dollar. The parents should ignore his demands for them to pay the balance (he will just run up more charges) and let him figure it out. Maybe he will have to get a job or he will find out soon how the credit card company will come after him and he won't be able to buy a car, house or get a credit card for years! If they give in, it will happen again and again.....next time it may happen for something much more expensive like a home, car, or even if he gets married and has a couple of kids.