Re: if S gets in will he be ok academically.
The highest of HAs graduate something like 92+% of their class IN FOUR YEARS and 96+% in six years. Those numbers tell the story; compare those numbers to lower academic tier colleges.
If a kid is good enough to have the academics and scores while developing his baseball skills to the highest level, he has earned his slot in an incoming class - by proving his devotion to an EC AND succeeding in academics. (As virtually every other kid.)
The Ivies DO NOT PROVIDE UNIQUE ACADEMIC ASSISTANCE to athletes; but the assistance available to all students is impressive: office hours, peer tutors, writing assistance, TA tutoring, occupational help- it's all there if the student seeks it out. Moreover, if for example, a kid isn't/doesn't want a math heavy major (e.g., Economics has become a math heavy major), history and Poli sci seem to attract many athletes. So, my answer is the kid will be fine if he simply continues his HS track record.
I submit, however, that the opportunities which await these kids dwarfs the risk that a kid goes off the rails and flunks out. (Which can happen anywhere.)
S was the recruited athlete, D got in on her own (with a set of very powerful ECs). Both were over the middle of the admitting class in scores and grades. S graduated dead middle in Econ; D a bit better as a ChemE. During the seven class years I knew Ss teammates, all remained eligible, all graduated on time (less two pro players who took an additional semester to finish), one left (out of 56ish recruits) due to MH issues.
But, the job opportunities; let me repeat: but, the job opportunities! Summer internships all over the world (or summer ball for those inclined), employment opportunities all over the world. Doesn't mean you can't return to your home town, but it means you can leave for anywhere you want.
For parents worrying about the kid being overmatched academically, the kids take some fluff courses (which actually can be fun); S took astronomy and History of Coinage, for example. He also wrote an original junior paper and an original senior thesis (as did every student) in economics. Prospective employers loved them and he learned how to do original research, communicate both in writing and orally, and apply his skills in the real world; he wasn't unique - every kid did it.
In another thread, I wrote about his teammates - five years after graduation. Look up that thread; as far as I can tell every Ivy is as impressive.
I'll leave with this moral: if a kid can leverage hs baseball into an Ivy do it; no baseball dreams are diminished and he gets a nice headstart in the job world.