Autumn quarter is an adjustment. The quarter runs quick, though fortunately now TG week is a full week off with no additional work assigned. If your son is worried about not having formed the study habits, he should consider taking three not four courses. Hum will be required, then he’ll want to take whichever Math he places into (likely a calculus) and then perhaps one of the sciences like gen’l chem which many find very challenging. Students are encouraged to form study groups and he’ll find plenty in his house who are taking the same courses. The professors will all have office hours. He should absolutely take advantage of them as well as problem sessions with the TA. Hum will include a required writing seminar with the assigned tutor and that person is also available throughout the quarter to help with your essays. And there are peer tutors available as well. So lots of academic support, as long as the student is willing to use these resources.
The student will be assigned a general academic advisor and a career advisor when they matriculate; a major advisor will be added on once they declare their major (usually it’s the undergraduate program coordinator or someone working for that person).
Not sure when the bio major would begin but I have the impression that most in the major or in premed begin their bio sequence in winter quarter. Then he’ll need to take four courses. His bio placement will depend on his AP score (if he took or is taking AP Bio). He’ll get a chance to meet with his summer advisor via phone or remote, and he can also peruse the gen ed and major requirements here in the catalog (it’ll update in the spring for his class): http://collegecatalog.uchicago.edu/
My kids are good evidence that if you just plug away at it and understand your strengths and weaknesses, you’ll do all right and likely do fine. Most students don’t drown; rather, they make choices - maybe trading off more time on calc for a B in Hum as just one example. Both of mine took Hum and Sosc together because close reading and writing was their forté; both also took calc but offset all that work by taking non-major science. The resulting schedule wasn’t a breeze, but it was definitely doable.
Some kids don’t do as well in high school as they will in college because the former bores them. If your son is excited about the opportunity to be part of the intellectual community at UChicago and is willing to devote his time to the sheer love of learning, then he’ll probably be fine. IMO, a kid who is properly motivated intellectually is a great fit for UChicago. However, kids who simply don’t want to put academics at the forefront of their collegiate experience might find the place to be too much.
The university orchestra is a great group of kids, from what I understand. Very very talented. They haven’t been able to perform or practice this year, but they still meet weekly via Zoom. My son has been involved in the ensembles since he came to campus and my D was in one of the chorale groups her first year (too busy with her part time job after that). They made friends in these groups but also with others in their house. If things are back to normal in the fall, then hopefully O-Week will return and your son will have lots of opportunity to socialize, meet his fellow housemates and generally have a great time before the start of the academic year. Don’t look at last fall as the norm. Covid made things very difficult with stay-at-home or even mandated quarantine, etc. Usually O-Week is a blast and a great time to hang out and meet others. The dining rooms all have house tables, too, and my kids always ate at theirs (not this year though, sadly - again due to Covid).
In short, there is ample opportunity for your son to make friends and have a blast of a time. But UChicago defines “fun” a bit different than other places. More gateway courses, less tailgating, if you catch my drift 