The only potential crime here would be harassment under the provisions of the Protection from Harassment Act. Harassment is a course of action (more than twice) which is intended to harass there is reckless as to whether it harasses and whether an outsider would look at what happened and think that it amounted to harassment. It may or may not be an offence in the country where he lives.
It would only become harassment in your case if it got out of control and certainly not after 6 minutes.
Just because he was on the phone or some other communication device appearing to speak to some law-enforcement agency does not actually mean there was someone on the other end!
I can tell you that if he went to the police in the UK with this, they would not do anything about it for a whole variety of reasons including the fact that there is not actually a crime and, they have better things to do.
Certainly, if this person is in another country, you will not hear anything about this. There is no need to worry.
The only time there may be a problem is if it was sexually or racially et cetera motivated which you haven’t mentioned so I assume is not the case. All this talk about it being a hate crime is just him spouting off. Don’t worry.
Can I clarify anything for you?
Please don’t forget to rate the service positive. It’s an important part of the process by which experts get paid.