The curious incident of the dog in the night-time 2

As I am getting close to the middle of the book, I get a suspicious feeling about the dad. First of all, he lied to Christopher about his mother dying. I understand that he didn't think Christopher could handle this, but he always taught him to tell the truth no matter what. Also, the fact that he wouldn't let Christopher write a book about his journey through finding the killer doesn't make sense. The best thing to do for a kid like Chris is to let him be peaceful and do what he wants in an isolated way. Finally, on page 109, his mom writes in the note, "And I remember looking at the two of you and seeing you together and thinking how you were really different with him. Much calmer." This means that his attitude toward Christopher changed since his mom left. His mom also said how she cussed more than he did and that he never cussed. His father always swears at him and insults him which is a bad way to act around someone with autism.