Your s/d won’t know if they can get a room change if they don’t ask! Your child has a right to be comfortable in their own room, and to have input in choices/decisions. Delicate responses like “I don’t feel comfortable with that”, or “I think I’ll take a pass on that” or the like is a delicate way of saying NO.
Reaching out the the RA is exactly the right thing to do. Alerts the RA to issues, lets the RA address it , so it takes the pressure off your child, and addresses the controlling behaviors of the roommate with a third party/neutral party but person with some authority. That is the RA’s role.