This was in anime. In DMC1 booklet and DMC 1 novel says Dante didn't know his father personally.Even in DMC1 game, Dante says it was his mother who told him how his father was.Really? Like what? Because Dante once talked about how it looked to him like his mother and father loved each other and other instances it doesn't sound like when Dante is talking about him to be a second hand account of it.
Same with Sparda's death: in some media he is given as "dead", in others just as a "disappeared".