The Solo twins- Jacen and Jaina- were childhood friends with Zekk, who was a street-wise kid who was also an orphan and not good at social graces. They never once considered Zekk might have force sensitivity to become a Jedi and train at their uncle Luke Skywalker's academy ,as they did. That mistake nearly cost them when he joined the Shadow Academy and began training as a dark jedi under Brakkis.