What Causes Sudden Voice Loss After A Head Injury?

My mother (63 yrs old) fell from bed one night and hit on head, shoulder and knee. She was doing okey until next 40 hrs of the incident. 40 hrs later, she was doing some cleaning in kitchen and she smelled an old food item, it has fungus on it, and suddenly after that she almost totally lost her voice. We though it may be due to some fungal infection in throat and take her to ENT specialist but he denies any claim of infection and referred to Neurologist and CAT Scan. We have an appointment with Neurologist tomorrow. ENT Doctor has prescribed few medicines for 2 days - Clopidogrel, Neurocalm and Neurogen. Two days later her condition is not much improved but she can speak just a couple words in a sentence at a time with her full force. Note that she had Breast Cancer 5 years back and she is diabetic. At present, she doesn t have any pain in neck or throat and she is able to eat and drink properly. She is able to do all her things properly, she can walk (even though she still have body ache due to incident), she can cook. No other body part is effected. There is no memory loss. She never had any voice related problem in the past. Please suggest what is the possible root cause of the sudden voice loss and what are the options available for its cure. What should be the next steps.