You could try moving him back to your room. Maybe he just misses being close to you.
I read recently on a training site that *any* attention you give them will only feed their behavior. You might try not responding at all to his barking - just let him bark until he can't bark no more
I know it's hard. Do you have neighbors who would be upset by that?
I need to follow my own advice. Daisy never pees at night, but she wants to get up several times. I have a hard time letting her whine because it's easier on my heart to get up, take her to NOT pee, and put her back in.