Re: Appropriate consequence
Are they sharing a room or is he going into the baby's room to wake them up? If they don't share I'd make him lay down in his bed the next time the baby naps. Tell him if he wakes the baby he'll go down every time the baby does. He may not mind at first, but he'll get tired of going down for a nap several times a day. If they share then make him lay down on the floor in the hall (my kids share and naps are sometimes done like this).