I misunderstood the part about the single room being occupied. I assumed it was already scheduled to become vacant at the end of the semester.
I now realize that may not be what the roommate is saying – he may be saying he wants to force the current occupant of the single to move into the double room with the OP so that the current roommate can move into the single.
@JAllenPrimack If that is the case, I change my earlier advice. I would not support the roommate in his attempt to force the current occupant of the to move.
I agree with the others who say your roommates issues with being a light sleeper are real and also entirely his responsibility. You’re being more than courteous. It is up to your roommate to find a solution for his issues.
The roommate try to do what they can to reduce the situation. They are…ear plugs, mask
2)You to try to do what you can: being quiet, using vibration alarm
I would suggest that the roommate look into Bose earplugs that can give you whitenoise.
The only thing he can do is get his own private room (but even then, people make noise in the hall). he may not be able to do that this semester.
I personally would not get involved other than to talk to the RA about how you tried to accomodate as much as possible. I would not pressure anyone else to move.