kick him out

Do you know his best friends and are any of them showing any signs of concern? Is there one or two of them you could have a real conversation with?

If you are lucky enough to find a friend of his to open up to you and for damn sure you must keep that conversation confidential, Take those words to heart and a professional.

I'm am certain your worry is real and like a good mom and human, you are looking for help with what you don't know or understand. Keep digging, the issue may be the death of the friend or could be teen boy angst from many different sources coupled with the loss of the friend. Good luck

Try to get him to see a therapist. Something has changed for him and not for the good. You will be his best advocate now. Fight for his future. I wish you both the very best.

As a decent parent its certainly hard to see but that is pretty normal behavior for a teenager.
I was shocking for years but I sorted myself out.
Those are the years where you are beligerant and trying to find yourself.

ive had it happen a bit...i think you just need to ride it out - short of chaining them up you cant do a lot to prevent it.

My son settled down a bit afterwards...

If you try to stop him, punish or scold him, it would make him more rebellious and the problem will worsen. Give him an environment where he can share and express himself to you openly. Get down to the mental level of kids of his age and understand what he has to say. Talk to him about all the taboo issues openly, you will have to break a million barriers to do that, but it will all be worth the effort to save your son.

You just need to sit with him and talk like a friend

I think the term is called growing up.

Where is his father? Are you together?

Sometimes you cant do anything. You just have to be there and try to understand

Give him a pack of condoms as a christmas present

How old is he?