The Vet checked his stool sample and did not find any parasites. I told the Vet that Seamus is been grabbing Stella's food from her bowl. The Vet thinks that Stella's food might have caused him some stomach problems.
The Vet also noticed that Seamus was a little dehydrated and gave him some fluids. He prescribed an antibiotic and put him on a chicken and rice diet for few days to see if he gets better.
Today, Seamus is been active and eating the homemade chicken/rice food. Hopefully, he has only an upset stomach caused by Stella's food. I will keep him on this diet for a few days and monitor him for any symptoms.