In order to find him, more research really needs to be done in Australia for him.
Is there not any clue in the wedding register who his parents could have been?
When did he arrive in Australia? Can you find him in any ship list? Is he in any kind of census? Application for citizenship?
As for the names, Charles would in Sweden been Carl/Karl, Alexander could have been Axel. Fagberg would been unusual, could perhaps been Falberg or misspelling of Hagberg.