He’s a 17 year old boy, and like everyone his age wants to be treated like a man. He saw his father come out, and in his mind he thought his father Coming outside to ‘get fresh air’ was really coming outside to check up on him. He was embarrassed because he felt like he wasn’t trusted and he felt like your husband was babying him.
For him partying in the middle of the night is normal and accepted so he doesn’t think that it would be embarrassing for you.