Is it wrong to fall in love with and sleep with a person that someone else in your family dated for only 2 to 3 weeks and never saw face to face and never messed around?

Sleepwalking can always lead to problems, just ask my Aussie pal, Raymond O. Skywalker.
He has got himself into all kinds of scrapes during his out-of-body sleep trips; such as walking into lamposts, walking into on-coming traffic, ignoring his mother when she was talking to him, and feeding the puppy-dog with food meant for the cat.