He might be depressed, so some therapy might be in order.
He's 18 year old, so he's an adult. Taking stuff he owns from him is not good. But the parents can take whatever they own from him, even the right to live at their parent's home.
So, the best course of action (in addition to explore some therapy for him) might be for the parents to negotiate with their son from a position of strength. If he doesn't like what is being suggested to him, he's free to get a place to live by himself. His home, his rules.
He might be depressed, so some therapy might be in order.
He's 18 year old, so he's an adult. Taking stuff he owns from him is not good. But the parents can take whatever they own from him, even the right to live at their parent's home.
So, the best course of action (in addition to explore some therapy for him) might be for the parents to negotiate with their son from a position of strength. If he doesn't like what is being suggested to him, he's free to get a place to live by himself. His home, his rules.