Nancy
Hi, I was a sleepwalker at that age and maybe even a lil older. I don't think that there is any remedy. I did go outside already, but my father was a light sleeper and just guied me back. I did many things, like move knick knacks around, we also had a dog and had a board that barricaded him in the kitchen, but i would cross it as though it was not there. My father put chairs in front of the doors, so that he could hear me if i did go out again. My suggestin to you is to get a latch, and place it at the very top of the door and the frame. Not from the side , but the top. Hopefully he will not be able to reach that. Oh btw, I grew out of it, if that's any consolation. Best of luck to you, Nancy