Why did the Tucks kidnap Weenie in Tuck Everlasting?

The Tucks kidnapped Weenie because they believed she would be a good companion for their son, Jesse Tuck, who was lonely and wanted someone to share his eternal life with. They hoped to introduce her to their secret of immortality and prevent her from revealing it to the world. The Tucks also wanted to protect Weenie from the dangers of their secret, as they felt she would be safer away from society. Ultimately, their intentions were rooted in a desire for connection and to shield her from the consequences of knowing about the magical spring.