Put him on a zero hour contract 
Sad, but you can see why business does it. In fact that is probably not such a bad idea - and I'm sorry if this case is a genuine one.
Taking on staff means you are a manager and you have to manage them. Sometimes you need to play mind games with these guys.
When I first came here 20 years ago, I got a temporary position in a service and retail outlet. There was eight staff. Being new I didn't know the history of anyone but within a few days the assistant manager took ill with a runny tummy and vomiting. The company allowed its staff to self certify illness up to 3 days, after that a doctor's note was required.
The following month the same thing happened. I phoned the personnel dept in Slough and we found that he was sick about the same time every month with a self certified sickness and diarrhea bug – a few days before payday for the last 2 years.
Anyway, I painted a picture of what this fellow would look like to the staff on the evening of the third day before we closed up. What would you look like if you had been vomiting etc for 3 days? No colour, loss of weight, drawn, sickly looking, etc. This was the mental picture they took home with them. So when he arrived at work fit and healthy the next day, they caught him out.
I never had to say much about this to him, the staff did it for me. All I did say to him was that the timing of every sick spell had been noted by the personnel dept and as it was a few days before each payday, we believe that you didn’t bother to come to work because you didn’t have money the put petrol into the car.
I was there in that branch for another nine months and not one person was sick. They were watching each other.