Are adult children liable for a parents debt if their parent dies?

No, they are not.  The estate of your parents are rsonsible for their debts.  They only way that a person can be responsible is if say they are co signors on a loan or if they are on a credit card and by that I mean on the original application, not just an additional card holder. If you have some concerns it may be good to seek help from an estate planner in your area.  Good luck.