David RandEditMax and his father were always close, but especially so after his mother and brother dying in the crash. After that they were all each other had. While David has a hard time understanding some elements of his son's actions and personality, in a way they're very much alike, with David being a lot more jaded than Max is.
David is the origin of Max's powers, as he clearly has the same power to a lesser extent, himself. While David can only experience concern about the presence of a demon as opposed to fear in most cases, in some he will find himself afraid. David was unaware of his powers, however.