I had an injection of Botox in my left calf. In was intended to help the severe dystonia I have in my left ankle, which is controlled by the calf muscles. I regret to say it didn't really help, and my ankle got so weak. It still is turning in when I walk. It was done in early March of this year. I can't say how it might affect your father, who knows, it may make all the difference in the world. I know it is very safe, and aside from the weakness, there are no side-effects at all. Jacob Drollinger