I was like this in college. I had an undiagnosed autoimmune disease. I would not say anything. It’s unhelpful.

I think you should encourage your dd to have a conversation with her that includes her telling her roommate that she should go to talk to someone at student counseling services. It's ok to withstand a little hostility if it's given with "I care about you." That's a lot better than if something goes really south and no one said anything. I would give it a week after that conversation and then call her mom, especially if you have a relationship with her, even if it's surface.

Worst case scenario she's pissed for a little bit. Best case scenario, she gets help that she needs.

Sleeping that long is not in the normal course of behavior and is a sign that something is wrong.

Being annoyed with your dd for waking her up means that she doesn't realize how much she's sleeping.

There is the other possibility that she has mono and doesn't realize it, but is exhausted. Either way, she needs tending to from a grown up, imo.

“She'll sleep in to 2pm, get up for 2 hours and go back to bed for 4 hours.”

How does your daughter even know this is the roommates schedule if your daughter should be going to class? And how does the roommate only have 2 hours of class a day?

My son’s roommate stayed up playing video games until 3:30 in the morning. And he snored. And sometimes he took phone calls and would turn off the light when he walked ti the bathroom at midnight and came back into the room.

My son would get up at 8:30 go to class and come back to his dorm room where his roommate would still be asleep. My son would then crawl back into bed at noon for a nap before waking up again at 2 pm for a afternoon classes. Then sometimes a quick nap before going to marching band practice in the evening.

The roommate’s mother came one weekend and as they were going out my son was about to take a nap because he had gotten up early, gone to an activity, showered, and just got back from eating lunch. The roommate’s mother made a snarky comment about my son napping so much. The roommate of course never explained to his mom that he was the POS roommate who stayed up late.

I was your daughter in the early 90s.
I called the parent as I did not know what to do. This was way before we had the language or support that we do today.

The parents were grateful and were able to help get their daughter the support she needed.

Please call the mom. Wouldn’t you want to be called?

I would want to know. I hope the roommate gets help.