God forbid an employee should work an extra hour unexpectedly. Hard to access the whole situation without all the facts but without extenuating services I would fire the guy.
Fact 1. There was a phone.
Fact 2. The supervisor should have called but did not. There is close to zero chance that company policy does not mandate this.
Fact 3. The supervisor needs to be fired badly.
Fact 4. If you are in a leadership position and think the problem here is that the employee needs firing while retaining the supervisor, you need to be fired.
Fact 5. You have no defense for fact five.
And I'd fire the manager. And probably whoever thought the manager should be a manager. Sounds like the employee might make good manager material. And that you would not.
Reasonable assumptions:
This isn’t the first time that this has happened.
On previous occasions, the manager did not authorize overtime or even straight time for the additional hours as to do so would expose the manager’s failings.
The manager accepts no excuses from employees.
This business is likely to fail if the owner doesn’t come up with a new manager - soon.
He did work an extra hour. How many extra hours do you think he should have stayed with no word from the manager?
Personally, I would have only given him 15 minutes then locked up and left, if there was no phone call.