Choose a different lake. (that's almost not a joke).
BUT,
There is no BAD place to take your dad out for a fishing trip. Just because I can't seem to catch a fish right now, doesn't mean for you to change your plans.

Dress light, lots of cold water and ice. It's HOT HOT on Dardanelle right now.
Stay on the lower end of the lake. Your best chance of catching some fish "seem" to be down there (illinois bayou/Ouita area) and probably before 10:00am.

Water down there looks good and friends have been telling me they been catching em down there.