As an informant for years Mateen actually helped to clear his terrorist son of any scrutiny by the FBI, then he killed 49 and wounded dozens of others.
None of that matters to me. First, the gunman is not his father; they are two different people. Second, none of that is going to bring the killed back. That piece of information changes nothing, if you ask me.
I'm not sure what kind of influence if any, his father had.
I think about my own father and what different lives and decisions we have made, even though we share DNA. Sometimes children completely develop completely different lives regardless of how much parents want to influence them in a given direction.