Just to give an update for Monday, August 22, so you can continue to pray:
As of about 3:00pm he had an uneventful night and day (in a good way). He is still in the ICU to be monitored. The doctors are doing some other types of tests, but have not found the cause yet. It is an encouragement to his parents that their daughter (one of Aaron's sisters) was able to come from Virginia and be there at the hospital with them.