<p>the kid wants many of the advantages of a child- the home, the care, prob free room and board, but wants to be considered an adult. Like many his age( me too, back then) he has a confused idea of what an adult is.
What would the OP do if I was a houseguest and “created havoc” in the household? Talk the problem with me, give me time limit to change? If I didn’t comply, I’d expect to have to move out.
Granted, this is offspring, not just a guest but I think much the same applies.
Adults don’t get to behave any way they want- without consequences- and that’s the part this near adult doesn’t grasp. All his life, no matter how he behaved, he had a place you had to provide. Now(at 18) this is no longer true. Now you provide a place because you want to help him progress toward independence.</p>