I'm going to question a co-workers lunch break
What is your reason for wanting to question your coworker on their lunch break?
Yes, I think he's supposed to work longer than he does.
That is none of your business. You shouldn't question your coworker and their break. That is their business.
I think it's possible he's using the time to do something else than eating. I'm going to call him out.
If the lunch break becomes a problem for you or your coworkers than it may be ok to ask. Do not ask if there are no consequences of the action though. Everyone deserves their privacy at times.