Yes he/she can visit. Lots do. Some have problems but many don't seem to. There is no 100% guarantee. Have your spouse take any documentation with them so if needed at POE can show they will be returning home......letter from employer, lease, things like that.
Have a read here.......It is a very good discussion on this issue.
http://www.visajourney.com/forums2/index.php?showtopic=58200&hl=wife&st=0Curious though. You have asked about K-3 yet under your ID says K-1??

so we are able to get an idea of where you are up to. It does help. It also helps with the statistics on VJ so all benefit.