My brother went thru a stage like this. And he was, indeed, sleep-walking. My Mom found him downstairs on several occasions, and he had no idea how he got there. She heard him up and about one night, and found him about to pee on his bed, standing like he was at the toilet. She just directed him to the bathroom, gently, being careful not to wake him up. Another time she found him about to pee in the hall closet! So I would say he's probably sleep-walking. Be careful not to wake him during those bouts. Just talk gently to him, redirecting him to where he needs to go, maybe gently steer him with your hands, back to bed, or to the bathroom. I know they have those alarms that goes under a mattress, and it goes off, if the person gets out of bed. You may want to go that route, so that you can be aware of when he may be sleep-walking, then you can make sure he's safe, and going to the bathroom where he needs to be. If it becomes a huge problem, I'd also speak to his pediatrician about it. They will be more help. Good luck with all of this!