I think you can request rooms with bathrooms if you have a legit condition, and IBD is definitely a condition that would warrant a toilet
I am happy he's doing well with remicade though. Hopefully the bathroom won't be an issue for very long, or at all ideally, but I think planning to attempt to get a private bathroom would be worthwhile. I know if i were in a dorm situation, I'd feel a lot better if I knew I wouldn't end up stuck sharing with a ton of people with a flare.