Administration of a drug listed on patient's record for known allergies that sets off chain events that result in death.Do I have a case?

Father, aged 79, kidney patient suffering from healthcare induced pneumonia was admitted to hospital (not ICU unit). Patient has know allergy to valium was prescribed ATIVAN 3X within 24 hours. Warning label for drug states: 1) The warning label states: Do not use Ativan if you are allergic to lorazepam or to other benzodiazepines, such as alprazolam (Xanax), chlordiazepoxide (Librium), clorazepate (Tranxene), diazepam (Valium), or oxazepam (Serax). 2) Major warnings for Kidney Patients Benzodiazepines (Includes Ativan) ¿ Renal/Liver Disease . 3) Major warnings for Respiratory Patients Benzodiazepines (Includes Ativan) ¿ Respiratory Depression 4) Drug is not ideal for elderly patients or patients in very poor health. Of which he was both. I assert that the administration of this drug set off a chain of events that led to my father's death and in my opinion administering this drug to patient with my father's medical history was either GROSS NEGLIGENCE or worse!