Let's Just Say He Was Caught Red-Handed

It depends on both the state and the company. A company can require valid reason for not working. Also, lying to your boss and being stupid enough to get caught can easily fall under "insubordination" which can be a termination in itself

At my job, they can require a doctor's note if you call out sick. Usually they don't, but they will if they think you are abusing the system (ex. You put in for a personal day and it gets denied, then you are magically too sick to come in that day).

That's his index finger, not his thumb. Thumbs don't have two joints above the knuckles