Elevated liver enzymes, depending on which are elevated, can be due to a variety of causes. If his ALT/AST are high (transaminitis) can be due to alcohol, hepatitis (whether this is A, B, or C), gall bladder disease, or medicine's he's taking (lipitor??). If it were gall bladder disease, you might see more of different enzymes elevated also, like alk phos or something. Is there any pain in his right upper belly? Does he look yellow (jaundiced)?
In addition, there are other liver enzymes that can be elevated and mean absolutely nothing like Gilbert's syndrome. I'm not sure exactly which enzymes are elevated, but be sure to follow up!! Hope this little bit helps.
mr justhat (about to graduate medical school--doesn't mean I know everything though!!!!)