i just graduated from my undergrad university and i'm just starting graduate school, and i've had T1 for about 8 years. you'd be surprised how helpful roomates are - and usually curious about diabetes as well. mine have been wonderful over the past four years, especially on nights that i might go a little overboard with partying and need help testing or being fed some food before bedtime. I'm not sure if your son is a "partier" (and that might change when he gets to school) but either way, i can't express how important it is for him to still go out, regardless of whether he chooses to drink or not with diabetes. choosing not to go out because partying with diabetes is a bad idea will only limit the number of great college friends he can meet, and making friends who will be a support net in other parts of life is so important. so tell him to have fun and don't let his diabetes limit his social life!
my RA did know i had diabetes but i never asked him to check on me. if your son has a roomate, i'm sure he'll notice if your son doesn't wake up one morning. maybe trying to get a class schedule where they're both waking up at the same time would be helpful in the future, so they know they have to wake eachother up every day. a lot of times when i'm switching dosages i'll set an alarm for halfway through the night for the first few nights of the new dose of insulin just to check how i'm doing - i'd rather wake up to an alarm, test, eat a snack if i test and i'm 90 rather than wake up an hour later low and feeling crappy and then eating.
college is definitely a challenge - stress was a big issue for me because when i had an exam coming that i was stressing about for several days sometimes i'd literally double my typical daily dose and still be 400 all day long. stress causes insulin resistance for me, so its worth it to try to do activities that reduce stress during exam times, like taking a walk or going to the gym. now that i'm starting grad school there's going to be a whole new level of stress in my life, and i've learned to take it a day at a time.
so, i'd say maybe a discreet text each day until he's comfortably moved in would be ok - calling is a little obsessive, and i'm sure the last thing a freshman boy wants (on top of standing out a little cause he has a disease that a lot of people aren't familiar with, and sometimes a bit freaked out by) is to have a mother who can't let go! good luck with everything - college was the best part of my life and i didn't let diabetes interfere with that, and i know your son will be able to do the same thing.