Bad behavior (and therefore bad kamma?) due to physical ailments

In this TEDx Talk Youtube video at timestamp 12m 36s, Dr. Daniel Amen told the story of a nine year old boy named Andrew, who attacked a girl on a field for no particular reason and he had other behavioral problems. It turns out that he had a cyst in the left temporal lobe of his brain the size of a golf ball. Once it was removed, he returned to being a normal boy with normal behavior. Questions: 1. If his cyst was caused by past kamma, and if his bad behavior is caused by the presence of the cyst, then this implies that his present behavior is caused by his past kamma and he has no control of it. Is that true? 2. If his bad behavior was caused by the presence of the cyst, then would Andrew be creating bad kamma (by attacking the girl) due to bad intention, or would he not be creating bad kamma (by attacking the girl), because it was due to the cyst and not due to his own intention? 3. What did the Buddha teach about the physical body (including brain) and its ailments or conditions, affecting the mind and kamma? 4. How do we avoid bad kamma, due to mind-influencing effects caused by physical conditioning? 5. How could Buddhist teachings help a person like Andrew (before his cyst was removed)?