C.W.
You and your husband are going to have to sit down with your son (without the other kids) and talk to him. He may be going through something and is afraid of talking to you guys. Take time out to show him that both of you care about him and his feelings and you're there when he's ready to talk.
I wish my parents were more open with me and made me feel comfortable talking to them when I was a teen; a lot of my issues and resentment didn't get resolved until recently because I've held it in too long and showed my anger and fustration in other ways, just like he's showing it through lying and being disrespectful.