Answer:
Frontal lobe
Explanation:
The brain is divided into four lobes which are:
the frontal lobe;
the parietal lobe;
the temporal lobe;
the occipital lobe
Each of these four lobes of the brain have their own unique function and damage to any part, would impair their function.
The frontal lobe of the brain controls important cognitive skills such as memory, language, problem solving, emotion, sexual behavior and judgment. It is basically responsible for the personalities and communications of humans.
In this unique case, the most likely part of the brain that is damaged is the frontal lobe because it is evident in the change in personality.