OH, I'm in the same boat as your son.
Straight A student in high school
..enrolled full-time in an early college program & while I got A's in my other classes--I got a C in Calculus and am facing a possible C in Organic Chem..
I've looked at each as a new learning experience ranging from time management to learning how to study for each class and ask for help!!
But, no, sad story telling to admissions is a no no.
Instead, talk about the risk and initiative he took by enrolling in such a program. (maybe?). So just wait til grades come out. Good luck to your son