Respectfully disagree here. There is no difference between English and Psych 101 at a JUCO verses Harvard and Yale. The young man goes to the JUCO and does well academically, he'll set himself for admittance to some of the finest academic four-year institutions in the country while saving himself thousands and thousands of dollars in tuition. The only thing that matters (on his resume) is where his final degree is from - not whether or not he attended a JUCO. Moreover, he'll have the chance to get better at baseball in the meantime and possibly set himself up for a better four year baseball opportunity down the road than what is currently being offered.
To the young man in question, you can always, always go back and "undo" a bad education decision although I admit - it will likely cost you a lot more money if that is the case. I know that JUCO, however, is not a bad education decision.
You cannot go back and undo a bad baseball decision. Pick the best baseball option "now" while the window is still open to you and absolutely make sure you follow-up on your academics after your baseball career is behind you.