Bongstar... I think that trying to understand how people like your father come up with the conclusion that "all things good came from Christianity" work is a key to opening their minds. There are many reasons that people believe that way -- fear and a lack of education being (IMHO) two of the most common reasons. Like, if anyone actually studied society before Christianity arrived on the scene, they would know that there were laws and punishments in place for instances of killing, adultery, etc etc (depending on what was deemed to be wrong in a particular society) long before the time of Jesus.
The fear is a by-product of the lack of education...fear of going to hell for not believing a certain way or living a certain way. And that's not to say that your father is stupid...and maybe even has an education...but obviously not in the area of societal morals and laws and behavior and religion etc.
There's a theory that
Jesus studied Buddhism...which I'm sure can never be proven, but the teachings of Jesus and Buddha are quite similar, which leads one to believe that there may be some connection.