In all fairness, I remember the father as 'telling' Pres. Bush to take a good hard look at his son...that it was his only son. I don't recall him coming out and saying that Bush "killed him". The father seemed to be on the anti-war side, that's for sure.
He did say that. One can understand his pain; one cannot understand a grown man using what is, likely, political hatred in a situation like this.
His son was obviously a better man than he is.