Although Ed Boone made some horrific choices, I would not deem him a bad man. Killing Wellington was inexcusable, but when we learn his reasons we see that he is a jealous man, whose past with women has not been successful. He lies to Christopher, but we have to ask.... does he think that the lie will be easier for Christopher than the truth. He has a difficult road ahead of him in raising Christopher alone.... is he merely afraid of Christopher's reaction, or is his lie something more.... possibly a bit of revenge against the woman who walked out.
In my opinion, Ed loved his son and put him first. He took the challenge and raised Christopher on his own, and he faced all of the difficulties it entailed. He did horrible things, he also did a lot of good things.