If the parents are married, then whatever they own jointly is subject to attachment by a lender…plus one spouse’s bad credit will impact the other’s. So not a good plan.
No one should take on debt they can’t pay, but the advantage of Plus loans is that there are more flexible options for repayment than with a HELOC or many private loans. They can also be consolidated and payment schedule extended, without any requirement to provide a reason. Those options don’t get rid of the loan, but they can be used to reduce monthly payment amounts.