Bill Due to Late Precertification for an ER Visit for my Deceased Father

Hello,

I had to take my dad to the emergency room because he had pancreatic cancer and was declining. He wound up passing away. I have the EOB from his health insurance for his hospital visit that has a patient responsibility of $0 for co-pay, deductible, and co-insurance. The hospital was in-network. However, there is a note saying the insurance would only be paying 50% of the amount due to late pre-certification. I took my dad to the hospital on a Friday night. He wound up getting discharged on hospice and passed away a few days later at home.

I called the insurance company, and they basically said that if we want to appeal it we can. I called the hospital up, and their EOB (which is apparently different than the EOB my dad received) says he has a $31,000 co-pay. What should be my best course of action. Should I try working through the hospital again to rectify the EOB discrepancy? Should I get a lawyer ready?

My mom is the sole beneficiary of the his estate, and cleans houses. She can't really take a hit of $30k.