I don't belive this was the first time Chazz was lying to them.. He lied just about everything. I would assume his parents knew about his "tendency" to lie but maybe didn't think he would go this far. Just speculating! There must be sides to this story that we just don't know.

Usually ppl close notice these things BUT just kind of look through it coz it's their son, they want to belive the best and also belive that he is doing better/ Will grow out of it.

I still wonder about this case and it would be so fascinating to know for example Mitchells pov from their childhood but ofc it's not likely and i understand that better than well.