On a serious note, be persistent with the medical angle. Maybe he has something chronic like colitis or Crohn's disease:

http://www.nacc.org.uk/content/ibd.asp

Someone has posted here who's husband had an issue with Crohn's I think, although I don't remember her name.

SM

"If we will be quiet and ready enough, we shall find compensation in every disappointment."
Henry David Thoreau