Can You sue someone who lied to a doctor??

[Liny07]

An accident occured in 2005 and we had tons of medical bills to pay so we got a lawyer. The medical bills were from the back injury and knee injury. In 2008 they had wanted to close the case but only paying for the back injuries. This was because in the year 2005 we had a lady come show us directions to a knee specialist and she had come with us into the room. Then later a nurse came in and asked questions about the knee and the lady who gave us directions interupted and said the knee injury was cause from falling down the stairs. Then there was an agument with myself and the lady which the nurse had also written on paper stating that we were arguing. We did not know that this was happening. The whole reason why we were sent to that knee specialist was because of the accident that had occurred. The thing is, our lawyer did NOT tell us that there was this part where this whole falling down the stairs thing was involved. We come to find out by the opposing lawyer. We had told the lawyer what exactly happen and said we can get this straighted out if that LADY can come clean from what she said. We talked to her and she claims yes she said that but it was a spur of a moment thing. Then a few days later the lawyer sent a letter saying that we Lied and dont want the case very unprofessional. Which had made a family member very upset to the point she was sent to the hospital. The letter affected her and makes her feel like she is a liar. She has told the whole truth the entire time. In this case. Is there a possible way you can sue that lady for lieing? Or the lawyer for writing an unprofessional letter that has affected her for 8 months cant eat sleep drive?? What should or can be done about this??