User blog comment:TemTheory/Season 15 Theory/@comment-79.115.77.84-20190428150951/@comment-26181040-20190428215119

No offense but their heroism is mostly based on personal interest. When they came for Mary. She wouldn't leave the Alternate Universe because of Bobby's Colony. So the brothers convinced them to go to their universe, out of promises that they will return to their world with tools and knowledge to fight Micahel. Which is basically a lie, to make they come to their world to get Mary to abandon the quest to kill Michael.