Sleepwalking is a very real disorder that can be dangerous to the sleepwalker and family members.
The National Sleep Foundation says there's no "cure" for sleepwalking, but there are things you can try to help prevent the problem and keep the sleepwalker safe:
Get more rest. A major trigger of sleepwalking is sleep deprivation.Avoid alcohol and any medications that tend to trigger sleepwalking episodes.Create a consistent and relaxing bedtime routine.Make sure the sleep environment is safe. For example, don't allow a child who sleep walks to sleep in a bunk bed.Keep doors and windows locked, keep any sharp or breakable objects far from the bed, and place gates above stairways.
Source:
http://www.medicinenet.com/script/main/art.asp?articlekey=176108