Following the death of his brother Edmund in 1900, Hitler went from a confident student who excelled academically to constantly arguing with his teachers and his dad. He eventually became obsessed with the ideas of German Nationalism and used it as a way to rebel against his father, who served the Austrian Government. His childhood friend August Kubizek claims Hitler to have been "a confirmed antisemite" before he left Linz around 1903.
These problems could be avoided if Hitler and his family relocated to America before 1900, and never become obsessed with antisemetic ideals. What would be a reason for them to come to America? What profession will he choose there? Where will he go to school?