My mom recently passed away -- will I be responsible for the medical bills that were not covered by Medicare?

"My mother, whose health had been failing for some years, passed away two weeks ago. She was phobic about doctors and would not go unless there were no alternatives, so consequently she would not participate in any form of insurance save Medicare Part A. When her condition suddenly worsened, she was transported to the ER via an ambulance. Tests were run and she was admitted. The next day she was moved to ICU and kept there for 24 hours. When it became obvious that there was nothing that could be done for her, we were apprised of hospice and arrangements were made to move her back home. She was released from the hospital at 4:30 PM and passed away the next morning in her own room. She had absolutely no estate (there is currently less than $100 in both her checking and savings accounts) as I have been her sole support for 20 years. She did receive a monthly Social Security allotment, which she insisted on using to help pay household bills and to purchase items for her own personal use (books, DVDs, vitamins). After this lengthy lead-in, my question is this: Will I be held responsible for the medical bills not covered by Medicare? Thank you for your help." — Anonymous Caring.com community member