This appears to be subacute intestinal obstruction
and is quite common in patients in the ICU
who are severely ill. A nasogastric tube will help reduce the stomach distension which is causing his abdominal swelling. Usually the distension reduces as a patient's condition improves and it can be helped by giving a patient nasogastric feed through the tube. However, this would depend on what is the underlying problem with your Grandpa. It would only become an emergency if the distension caused a perforation of his bowel.
Hope this helps.
Dr K A Pottinger,