I’m about 6’'2" and I wish I were about an inch taller. I have no idea why but for me, 6’3" or even 6’4" seems ideal. That’s still pretty tall but without being freakishly tall. That said I guess my small frame makes 6’2" somehow work.
FWIW, to the OP, there’s nothing wrong with being 5’7". I’ve seen plenty of women date shorter men, provided that they are still considered to be masculine. In almost all cases I can think of, the shorter men who have attractive women are muscular and athletic, not freakishly so but definitely above average in this regard. In addition to that, they are also usually charismatic and highly successful in their pursuits.
If you’re worried about your sons ability to attract women, I’d head that off by helping your son develop into a ‘well-rounded’ adult. Encourage him to be physically fit and at the same time, push him to succeed academically and professionally. Help him find some hobbies and worthwhile pursuits. Whether he’s 6’7" or 5’7", nothing attracts the opposite sex more than success.