Why do you think Mr. Boone lied to Christopher? Was he justified in doing so?

I believe that Mr. Boone felt he was doing the right thing.... he was simply wrong. Parents sometimes have to make difficult decisions, and unfortunately, Mr. Boone's decision reflected his own anger at his wife's abandonment of both he and his son, rather than basing that decision purely on what Christopher might want. Christopher deserved to make the decision about whether or not his mother would have a place in his life on his own, something that might possibly have happened. He wasn't given that chance, and he blamed his father for it.

I think that Mr Boone knew that it would be hard for Christopher to understand. I think that Mr Boone also wanted to live in denial. By saying that Judy had passed away, he didn't have to 'accept' that she left him. I think that at the time he thought he was doing the right thing. I do think that he intended on telling Christopher the truth but the longer he waited, the harder it was. I hope this answered your question a bit aha :)