A person of a young age could possibly live without the frontal lobe. This is known as plasticity the ability of the functions of the brain to adapt to its injured state, and to make sure the body continues to survived. The frontal lobe only controls our emotions and feelings. It does not affect our intelligence, knowledge, learning skills, and memorization. Those are controlled by the hippocampus, located inside the brain. Most people die from brain damage to the cerebrum or the foramen magnum, where the brain and spinal cord connect.
 
Now you know.