Stanley seems to value Jack but could not be bothered to remember his name. When Stanley attempts to flee to Faq Jack is the only person he specifically brings. Jack seems greatly loyal to Stanley for some reason and has turned down the opportunity to turn side.
Stanley seems to have come to value Jack more, possibly after Jack saved his life in the conflict with Jillian and the ten Warlords of Transylvito. Stanley noted that he was "trying to get better about names", presumably as a result of the problems with Jack, and Jack saving his life in that battle.