If he were behaving the same, but instead of gaming it was working or studying, would you feel the same way?
What if he were studying the equivalent of "basket weaving"?
It's definitely obsessive behavior, but it sounds like that's how your son is wired. If you want your son to be happy, start supporting him unconditionally and stop making him feel judged. If you want him to be exceptional, be patient and odds are he will eventually direct his obsessive behavior towards something valuable.
That sounds like a normal college-aged kid that’s still learning about life.
When I was in college (before streaming TV) they played X-Files for 4-6 hours each night starting at midnight and I’d stay up all night watching.
After getting my first real job, I remember seriously trying to figure out how I would record all 6 hours each night (how many VHS tapes and if I’d need multiple VCRs), and how I would fit 6 hours of X-Files into my evening each night after work.
Then I realized, “I guess I can’t watch X-Files anymore”. And I stopped watching X-Files.
Discuss with him the options and paths in front of him, including your concerns that gaming might be the symptom of something more serious, and that you love him no matter what, are here to support him, and that even if he dropped out of school, while you’d be very disappointed you would still be there to support him no matter what.
Then you let him make choices and learn from them. Sometimes people have to fail in order to learn. You literally can’t convey to someone what it’s like to burn their hand on the stove. You have to give them the freedom to touch it. And then they know.
I'm in my 30's now. I did the same exact thing, with the same completely whacked out sleep schedule, when I was transitioning 18-19. I spent thousands of hours on Oblivion. My parents did not get on my case about it. They did occasionally say "don't be late for X," or "you're going to miss Y," but they never blew it out of proportion to what it actually was, which was "just a phase" for me. I had very bad grades at this time, and gaming was a way to cope an escape; not the cause of it. My advice is to give him some space and let it play out. If he's going to fail something, let him fail and learn. Let him have a bad semester. He will bounce back. Perhaps this is unavoidable at this point.
A person can be addiction to something (like a game).
Or a person can be addicted to avoiding something (like his real-world life) via addiction- or OCD-like obsession with something that's both (1) readily available in quantity, and (2) well-suited to keeping his mind off whatever he's avoiding.
And of course there are overlap situations, and shades of gray, and possibly multiple things being avoided, being addicted to, and being used as distractions.
What if he were studying the equivalent of "basket weaving"?
It's definitely obsessive behavior, but it sounds like that's how your son is wired. If you want your son to be happy, start supporting him unconditionally and stop making him feel judged. If you want him to be exceptional, be patient and odds are he will eventually direct his obsessive behavior towards something valuable.