What do you mean your boyfriend’s alcohol consumption has never negatively affected you? He’s in jail because of his alcohol consumption! Doesn’t that negatively affect you? And why are you so sure you would have a “safe, happy life” with this older incarcerated alcoholic who lives six hours away from you and hasn’t yet been rehabbed or “found the roots of his issues so he can truly be happy” anyway? There’s a lot working against the success of your relationship (your age different isn’t even the biggest factor). You must be aware of that on some level or you wouldn’t be writing to me, no matter how deep in denial you currently reside. If you take nothing else from my advice to you, please take this: you should never, ever make long-term plans with someone who doesn’t have his problems “under control” yet. That he’s making plans to find the root of those problems or whatever isn’t enough.
I believe in redemption and I think people can change, but the fact that he isn’t redeemed yet means you should not be envisioning making a life together “some day.” I’m not even going to get into what it means that he “fell asleep drunk in the wrong apartment” and ended up in jail. I mean, if that doesn’t scare the hell out of you already, I’m not sure what I can say that will. But I will say this: be careful.
As for your parents’ potential disapproval, you should listen to them if they voice their concerns and consider whatever arguments they might have. Parents certainly don’t know everything, but they often know a lot, and as long as they’re supporting you in some way, you need to respect what they have to say. In the meantime, live your life. You’re 18. You’re in college. Go out with boys your own age. Socialize with friends. If this guy is so important to you and what you have is so special, it will be there down the line. Hopefully, way, way, way down the line.