Repeating Junior year

My son is a junior at one of the top all boys day school I the country. What are his opportunities to repeat junior year to grow academically and socially? He’s a fantastic young man. He loves Latin and math but struggles in English and reading comprehension.

When deciding to repeat a year, I think you should ask if ‘more of the same’ will help. Why is he falling behind? Was he ill? Is he really young for his grade? Will it be a big social ‘fail’ for him? Is there another option like taking a PG year before college?