My father who has conjestive heart failure and type 2 diabetes recently underwent a quintuple heart bypass. His medical bills are staggering and he ha

You could offer to pay immediately at the same discounted level those bills would have been paid by a health insurer (Blue Cross and HMO have agreements with the hospital and medical/surgical providers to substantially discount bills). That's a very substantial discount from the full "list price".

If that offer is not accepted, when he is sued, he might be more successful by saying the discounted price is the "reasonable and customary" price, rather than the list price they are seeking to collect. This approach is based on the fact that the discounted rates are what they receive on the majority of payments. He could do extensive pre-trial discovery to make them disclose their actual reimbursement rates (they would likely settle rather than disclose).

This whole process could be handled far better with the help of an attorney. If you don't have the money and fear bankruptcy is his only recourse, see a bankruptcy lawyer soon as Congress is about to change the bankruptcy laws and make it very difficult to wipe out bills.