What does Most demanding course schedule mean?

Stanford:
We expect applicants to pursue a reasonably challenging curriculum, choosing courses from among the most demanding courses available at your school. We ask you to exercise good judgment and to consult with your counselor, teachers and parents as you construct a curriculum that is right for you. Our hope is that your curriculum will inspire you to develop your intellectual passions, not suffer from unnecessary stress. The students who thrive at Stanford are those who are genuinely excited about learning, not necessarily those who take every single AP or IB, Honors or Accelerated class just because it has that designation.

My son has an LD (dyslexia) so opted not to take any AP classes with heavy reading loads. He took 6 out of 7 AP science courses offered by the school (couldn’t fit the 7th into his schedule), 3/3 math APs, and AP Spanish (10 total). The school offers 22 APs and the valedictorian usually takes 16 or 17. With straight A’s, son’s in the 7th percentile GPA-wise, taking the highest level classes he thought he could handle. Only applying to engineering programs, only one Ivy (Cornell). Counselor and colleges all have the info about his LD so we are hoping he doesn’t get dinged too badly if she reports his schedule as Very Demanding instead of Most Demanding and the fact that he’s not in the 5th percentile. We really didn’t know until this year how much his LD has held him back, because from his perspective it hasn’t at all!