My question has to do with modest dress and sleeping. I understand the rules concerning dress while in public, but what about when you are alone with a roommate when you are in bed trying to sleep. Like I usually like to sleep shirtless in boxers when it's hot out. I only would do this alone or with a roommate of the same gender, but would this be considered immodest; or does it not matter since it's done in private?
This would be no different than changing in a locker room. It is not considered immodest because incidental nudity or inadequate clothing is a part of two guys sharing the same sleeping quarters. You try the best you can to minimize the exposure, but it can't be totally avoided.