Mister Eternity by Maggie Hamilton

Mister Eternity by Maggie Hamilton is basically a crime book for children set in Kings Cross, Sydney. Sebastian and Josie find themselves enmeshed in mysterious events after their elderly friend, Lil, is bashed nearly to death and her home set on fire.The teenagers had been visiting her only hours before having their futures read in tea leaves. Now, they are on a quest to find out what really happened to their friend and to discover what it is people seem to be after in her apartment. An elderly gentlemen appears in Sebastian's life scribing the word "eternity"on the sidewalk outside his apartment building, and Sebastian instinctively knows that this man is part of the puzzle. Sebastian has problems of his own at home, like his mother he misses his dad and his brother Scotty who were killed in a trucking accident and now his mother is thinking of selling up and moving out of Kings Cross. Sebastian is devastated at the thought of leaving his beloved neighbourhood and dreads the idea of having to move in with his cold and authoritarian grandmother. Then, suddenly, Razor, an old friend is found murdered and the two friends know they must act quickly to save Lil who has mysteriously been moved from the hospital to an aged-care facility  called Greystaines in the outer suburbs

According to the author, Maggie Hamilton, Mister Eternity was inspired by the life of Arthur Stace, a reformed alcoholic. She has dedicated her final chapter of the book to him Further information can be found at:
http://en.wikipedia.org/wiki/Arthur_Stace