Wendy, I'm sorry to hear that dad is having to go through this. Did the yogurt seem to help at all? If it did then you can get the Probiotics in different ways.
I've noticed that Phillips is now advertising something that has them in the tablet (or whatever it is) or you can order it special from the pharmacy at Wal-Mart.
Being that you are so concerned about the exam, I would ask many questions before allowing it to happen.