Unbreakable/WMG

Those kids grow up to be Batman Style Superheroes.
The kids who were home invaded are pretty much average ordinary people. Though their parents are dead they never forget the hero that saved them from the same fate. They would want to be just like him one day. They would be To David Dunn what Batman would be to Superman.

Joeseph will get superpowers.
Because he is only half of David he would get some powers but not all of them.