The problem here is you. You've allowed your son to escape responsibility for himself for far too long. Being sheltered at home, he's had little reason to work towards building a career, find a life purpose, or start his own life. You've provided a much better deal than he'd get on welfare, which is why he's taking advantage of you.
Your son is more than capable of taking care of himself.
It's time for him to start taking care of himself and making his own way in the world.
Originally Posted by Naunnie
Did he try to sell you that line? In most locations, 18 is the age of legal adult status. Once a legal adult, you have no obligation to care for him. There may be medical exceptions, however your son is not in that category...
He's an adult and he's not paying rent. You don't even have to give him notice, you simply tell him to leave. You can even have the police escort him out if necessary.
If by some chance, he's ever paid rent or made some contribution to the household, you might have to give him 30 days notice. That's a stretch, but it's possible. But even then, after the 30 days he's a trespasser and he has to go.
I understand you are disappointed he has not taken these first steps into life willingly. It's tough to "kick out" a child, but it is necessary for him to grow and develop as an adult.