Hi, I had a later diagnosis than him. I didn't get diagnosed until after I graduated when stress had me by the hands. I managed to get through college because of how easy it was to register for classes. Class registration was easy and neat since it was online. The most difficult thing that I found was keeping up with the financial aid paperwork and my parents helped me with it so it made college a lot easier. Maybe he needs support on that side too. Have you asked him what he was having a difficult time with?
The problem with roommates is that they will party and be inconsiderate of resting time. I had a few places to go and I lived on campus. Eventually I had to get my own place so I ended up renting an apartment unit not far from campus. I use to major in Architecture so I was either in the dorm room or at my studio and then later on started visiting the library on campus. I have Asperger's Syndrome and I am diagnosed with two different forms of anxiety, major depression, and ADHD. I have dyslexia too, but its not diagnosed. I wrote pretty quickly and wrote everything the professors said to avoid reading. The only reading I ever had to do were homework problems.
Practice organization early on. I kept all my notes in a binder and my classes, if there were PDF versions, were saved in their own course folders. Spiral notebooks make me uncomfortable but I can put up with them sometimes. I don't know what else I can share right now.
I know I just regurgitated my college experience. Let me know if you have any other questions.