Sleepwalking, formally known as somnambulism, results in walking or performing other complex behaviors while asleep; it is much more common in children than in adults; and is much more likely to occur if a person is sleep deprived. Of course, as a very effective sleep aid, cannabis should help most people who are sleep deprived and therefore reduce the chance of a sleepwalking episode.
However, unfortunately in regards to sleepwalking, cannabis extends the restorative deep stages of sleep (stage 3 and stage 4 sleep), which are the same stages sleepwalking most often occurs, thus increasing the chances of a sleepwalking episode.
Simply put, cannabis’ effect on sleeping patterns increases the chances of having a sleepwalking episode. Therefore, unfortunately, my opinion is that cannabis would not be a good choice as a treatment for sleepwalking.
For more information on sleepwalking,