Have you put him back in his bed? Right now he gets up, he comes in, he gets to stay. it's an acceptable thing in his mind so why change it. When he gets up and comes in, reassure him as you escort him back to his room.
My two are older - not a lot, but older. They're 8 and 6. When they wake up from a nightmare or whatever unsettles them, I hug them tight. I tell them they're ok. I listen to their dream. I reassure them that it was just a dream and help them imagine up a new outcome to the dream that got them up. Tuck them back in. Kiss 'em. And rub their back a moment before leaving the room and going back to mine. If they get up again, I walk them back again. It's the same process since they moved into their own beds at 2. They learned this - we're there if they need us to comfort or care for them. But, when it's time to sleep again, it's in their own bed.
It's not the solution for everyone but it is for us.
at 11:57 PM on Oct. 5, 2010