Appreciate the perspective and advice. He was independently successful at home during HS, *but* he still had plenty of external structure in that he had school all day long, sports practice every day and Saturday, etc. ... so not loads of free time to manage. Agree this is not insurmountable and he's certainly not the first kid to flounder his first semester at college; just trying to be sure we consider all the potential paths.
What we've learned is that the prof can make a huge difference - same class taught by a different one can be piece of cake while the prof you got doesn't curve, piles on the work.
Yes, I don't like to call those freshman classes "weed-out" classes but my son did say that almost 50% of the kids at his uni fail the Chem class and Calc II.