How does Josh decide he will draw his family tree?

Josh and Atlas drive to Tim's. Josh and Atlas talk and Josh sits and thinks outside Tim's house. Josh tells Atlas that he imagined his dad was poor and could not afford to get to Boston. He even thought maybe he was handicapped and could not drive. Josh sees, though, that his dad has a truck and he never even tried to find him. Josh decides that his father does not deserve him, and he tells Atlas to leave.