I can only offer my personal history and confirm that 14 is a turning point age for boys. Hormones are rocking the crap out of your body and perfectly polite and obedient boys become rebellious.

I had a strong desire to be independent at 14 and this was the year I started Smoking, first time for getting drunk too. I was doing everything I could to keep away from my wonderful parents and I dont know why really. 14 was a pretty full on year for me and all the other boys at school too.

There is a Book on raising boys by Steve Bidduph that reccomends more intensive attention at this age but from someone else. Apparently Boys need exterior role models that are not their parents. Maybe he is interested in Joining Army/RAF Cadets or getting a part time job or something like that.

I got a job when I was 14 and it seemed to keep me from going silly but also gave me money to afford loud stereo equipment so there will be a household tradeoff there.

Also, as a professional BS Artist, when you fear you are being lied to, once your DS has stopped speaking just leave a nice big uncomfortable pause after what he said while staring at him with a blank face and see if he feels the need to further justify his statement. you can bring nervous behaviours to the surface you to see. (touching face, looking down, looking up to his left, scratching arm, fidgeting feet)