B.C.
I think some teens need to separate themselves emotionally from parental family as a way of eventually gaining some maturity.
They act out quite a bit to push the old boundaries - and do their level best to drive you up a wall.
He's an adult now and that comes with some perks and responsibilities.
He is now able to marry, join the military, enter into contracts, take out student loans without parental permission and if caught committing a crime he can be charged as an adult.
On your end - you are no longer obligated to provide him with food, clothing and shelter.
You don't have to pay for his car, gas, car insurance, cell phone, computer or devices either.
Not that you wouldn't help him while he's in college - but you are not legally obligated.
Which means you can stop offering support when ever you want to.
It's nice if everyone knows where they stand.
A re-negotiation of boundaries is needed.
You and son sit down and decide what the new rules are - both of you need to decide what success should look like and then take the steps that need to happen to make it happen.
If he could afford to live on campus you would not know where he was, what he was doing or when he was doing it.
I lived at home while I was going to college.
There were no cell phones back then.
All my mom wanted me to understand was that she was the wage earner, she paid the bills, she needed her sleep - and do NOT disturb the wage earner unless it was a life and death emergency.
So I could - and did - come and go as I pleased pretty much around the clock.
The fridge was our message board - all communication/notes were left there for the other to read - and for a few years we hardly knew we lived in the same house.
She went to bed before I got home, she went to work before I woke up, I'd be at school when she got home, etc.
Back then working on a computer meant you spent a lot of time in a terminal room on campus and if I had a project that required working through the night I'd call home (pay phone - I had to keep some change on hand) and let my Mom know I'd be pulling an all nighter.
But this wasn't contentious - we weren't arguing or fighting.
When grades came out I let her know the grades I earned.
If our schedules were open we'd do things together - see a lilac festival, see Sha Na Na, or take a trip together (we shared the driving)..
If I was traveling long distance by myself - I'd call home to let Mom know I got there ok.
It became less of a parent child relationship and more adult to adult relationship - and that's certainly an adjustment for everyone involved.
There are lots of things he could be doing all night.
Video gaming could easily be it - and preferable to sex and/or drugs.
From teens to mid 20's it's easy to burn your candle on both ends.
He'll out grow it eventually.