That includes things like: free metered parking, parking in no parking zones, parking on streets that require permits, spots with time limits, parking on a street for more than 3 hours, etc.
Visibly displaying that permit without the presence of the permit holder in order to access these other exemptions is a violation.
Where exactly did your father park the vehicle when he was receiving the ticket?
https://www.toronto.ca/311/knowledgebas ... ities.html
It's possible the parking official went over board.