Sometimes the discs do come back to you. All three of them are in a difficult place to search through. I've had friends who have had discs returned from near these areas so you never know.
It was a fun day to be out on the course and I always value time spent with my son.
The time spent with your son is obviously the highlight of the outing! I am sure you will eventually get the discs back, but time is more precious! Take care!