Is there a law firm htat will take a Malpractice Death Case without a retainer fee and willing to wait for payment until after Case is won????

I have very good reason to believe the hospital my deceased mother was in caused or contributed to her demise. She herself as a retired nurse felt she was grossly mistreated while in the hospitals care. She was fighting a urinary tract infection and was subjected to having to sit in her own feces for hours on end. At least 6-12 hours while receiving antibiotics intravenously for her condition. She literally being poisoned by her own feces due to lack of proper care. this lack of care caused her organs to break down and fail. Although she was 81 yrs old. prior to her prevailing condition. Her PA would constantly tell her, that inspite of her severe rhuematoid arthitis all her organs were in perfect operating condition. I have both witnesses and volumes of documentation, in the guise of charts and records of visiting nurses and therapeutic personal that provided services for her.She confided in me before she passed she wanted to sue the hospital for the terrible treatment she received.