Paranoia Support Group
Paranoia is a disturbed thought process characterized by excessive anxiety or fear, often to the point of irrationality and delusion. It is often associated with psychotic illnesses, sometimes schizophrenia, although attenuated features may be present in other primarily non-psychotic diagnoses, such as paranoid personality disorder and obsessive compulsive disorder.

"If you think someone is following you, turn right at any street, and keep turning 3 more times. If they are still following you, then call the police."
Hopefully, he will focus on that and realize that no one is following him.