Johnny is a normal, average 12 year old boy, who has a mobile phone and usually mucks around with his friends. He is a witness to The Pulse. He and his friend witness one of his friends get killed by one of the phone crazies and also finds his mother is turned into a zombie. After receiving a bad dosage of The Pulse Johnny loses most of his memory, and loses the ability to function. Clay puts a phone to his son's ear, hoping to send his son back to normal.
Whether Johnny regains his memory and ability to function or turn into a phone crazy is unknown. If he does turn into a zombie, it is likely he and his father would both be killed. But if he is sent back to normal, it is likely he would live the rest of his life with his father in the apocalyptic world. His mother is deceased.