Woah op! You are obviously a really great, conscientious mum, and your ds is lucky to have two caring parents, but you need to take a step back!
Your ds is no longer a child, nor is he “horrible”.
He’s a young man starting to individuate in to an adult which is a normal process. To achieve that he needs to question and reject some of the values and norms he’s been brought up with, and find some of his own, and of course fitting in with friends and vaping is all part of that.
I am not saying that vaping is good, or should be encouraged, but you need to give him the facts, for example, a couple of leaflets about collapsed lungs, then trust him and the strength of your relationship that he will see the light and make the decision on his own to stop.
I think you may not have much success imposing a ban from the top down. A better approach is “I am interested to see what decision you make, you are an intelligent young man and I have every confidence that you will make the right decision to protect your health. Don’t be a sheep etc”
“I wake him up, make his breakfast, load his stuff in the dishwasher, make his packed lunch. Then I encourage revision (nag apparently..) make tea, clear up, walk the dog, do the bins etc etc. No expectations on him at all other than exams and revision.”
^^ Also op, when I read the above paragraph my immediate thoughts are, “why?” Why are you doing all of these things for your son? I know it comes from a place of love but the underlying message he is receiving is “you are not capable”.
By the age of sixteen he should be responsible for waking himself up and getting out of bed, making his own breakfast (I suggest he should be cooking one or two evening meals a week too), be responsible for his own lunch, either making it or buying it himself, he should be loading and unloading the dishwasher, doing his own laundry and helping out with chores like bins etc.
My dds were doing their own laundry at twelve and were cooking a Friday night meal for the entire family at sixteen!
I understand that you want him to do well academically, but if he does well in his GCSEs he will be off to uni in two years. How do you anticipate that he is going to look after himself if he doesn’t know how to cook, clean and launder his clothes?
Aside from the above, you doing everything sounds really stifling op. You are treating him like a ten year old!
No wonder he is rebelling a bit! Behaviour is communication op! And his behaviour is saying, “I am more grown up than you realise, I have friends and activities that you don’t know about or don’t approve of because I am growing up and I can make my own decisions” instead of having every decision about his life made for him!
So take a large step back op! Get busy with your own life and develop some hobbies and interests that will serve you well for when your son leaves home in two years. Stop doing everything for him. Support, advise and cheer him on, but from the sidelines, let him steer the boat!
Good luck 🌷
Edited to say: sorry have just seen your update about him doing some chores so please ignore that bit of my post.
Have also just read your post about him going on to college and doing an apprenticeship and living at home for the next couple of years. In that case imho it’s even more important that you transition over time from mother-son to “two adults sharing the same space” or you will still be washing his smalls when he is twenty and you don’t want him to expect that from a wife or partner!