Someone correct me if I'm wrong, but he don't need a license till he is 16. So he can go with, call, and assist in anyway he wants, just can't shoot it for you.
Interesting...after double checking the regs, I think you may be right and what you are bringing to light may be the trump card. (Refer to page 9 of this years Iowa DNR Regulation pamphlet.)
From the DNR publication...
All Participants Must be Licensed - All participants in a hunt must be properly licensed and have paid the appropriate fees. Participation includes, but is not limited to, handling firearms or ammunition during the hunt, trying to attract
game, driving, flushing, or locating game, and working dogs.
The following persons do not need a Hunting License and/or pay certain fees:
1a) Residents under 16 years old who hunt under the direct supervision of their properly licensed parent, guardian, or other competent adult with the consent of the parent or guardian do not need a Hunting License or pay the Habitat or Migratory Game Bird fee. One properly licensed adult must accompany each unlicensed hunter under 16 years old.