Dear Don,
Hello, I am sorry to hear that your Dad is having problems. I would have a hard time diagnosing a specific problem with the
description that you gave. The pain of his extremities needs to be evaluated as does his liver distention and fatigue.
He needs a general examination and neurlogical examination with blood work to determine if the pain in his extremities is caused by a muscle problem or secondary to neurologic problem. He could have an infection of his liver that
is causing these problems as could more serious conditions. He needs a complete evaluation including an exam and potentially CT of his liver to see why his liver is large and blood work to start with. Hepatitis is an infection of hte liver that can give fatigue and generalized body aches with fevers and there are many causes of Hepatitis, mainly viruses. A GI or Gastrointestinal doctor specializes in liver problems so if this goes unanswered after many atttempts at finding a diangosis you may want ot find a GI doctor.
I wish I could help more but the details you gave me leave a long list of possiblities and the first step is always to take the least invasion approach at diagnosis problems beginning with a good exam and going from there. Good Luck!