He is probably being harassed.
Harassment is defined as a course of action (more than once) which is intended to harass, does harass, is reckless as to whether it harasses, or if the average bystander would look at the conduct and think that it was indeed harassment.
Harassment is both a civil matter and a criminal matter.
If a person is being harassed, they can go to the police and ask them to warn the alleged culprit under the Protection from Harassment Act. Some police forces take harassment very seriously and others not so and therefore, the person who is being allegedly harassed may need to speak to a senior officer or put a complaint in writing to the Chief Constable.
You can of course apply to the County Court for a civil injunction to prevent any contact and if the person then breaches the injunction they will get arrested and potentially jailed for contempt of court.
Contempt of court is actually more serious than the harassment itself.
Thank you for letting me assist you with your legal question. I am glad that I was able to help.
I am not certain whether that answers the question for you or not, but I am happy to answer any specific points arising from this.
It will be my pleasure to help you again either further with this or any future questions you have