What did Christopher's dad teach us about parenting? Why did Christopher's dad think lying was the best option?

All in all, I think the most important lesson we learn from Mr. Boone is that it's best to be honest.... even when honesty hurts. Ed Boone's greatest mistake is to lie about his wife leaving them. He thought he was protecting Christopher, and he didn't want Christopher to feel rejected, never dreaming that the secret would be exposed and rather than be angry with his mother for leaving, he is angry at his father for lying to him.