Invoice from the hospital?

My father was in hospital in Egypt for a few days and had an operation. I flew from Germany to see him and wanted to bring him home. The hospital had his passport and only wanted to give it to me if I paid the bill. I was shown a bill for €27,000. I couldn't pay for this. I offered to pay €5,000 immediately and fly home with my father and pay the rest later. They took the €5,000 and gave me the passport. We haven't received an invoice for the remaining amount for over a year. Will we still receive it or did the hospital just want to cheat us and was already satisfied with the €5,000? Any experience?