I would give him access to food and water in that room for now, until you can pinpoint the cause of this. It could be moving from that room is very stressful, so opting to not is very bad for a rabbit. If a rabbit goes a while without eating hay, it can become very ill, potentially causing GI stasis again for him. Some more information would be helpful to pinpoint the cause.
1) Any changes coinciding with this?
2) How long has this been happening for?
3) How old is he and your other rabbit?
4) Are either of your rabbits fixed? If so, how long?
5) How is the rabbit in questions poop and pee? How do they look and how frequent do they occur now?
6) What is his diet? What foods are he giving?
7) How much does he weigh?
8) How long have you had him and your other rabbit?
9) How often do you spend time with him?
10) It sounds like he’s free roam? What’s the cage or lack of cage situation for your rabbits?
The more information, the better.
The answers provided in this discussion are for general guideline purposes only. The information is not intended to diagnose or treat your pet. Seek the advice of your veterinarian or a qualified behaviorist.