Don't let people like that into your house. It can be dangerous for you.
On the other street in my community there is a boy. I've always thought he uses substances. But, the other day when I was on my way to college I heard him talking to a girl. Like the boy you describe, he was saying incoherent things. There I found out, that maybe he suffered from schizophrenia or something similar.
Anyway, I avoid going through there, because it becomes aggressive.
Solo dejo familia entrar mi casa normalmente o asociados del jale.
Este individuo llego de la nada. Si llega de nuevo no veo otro opción pero que decirle que se vaya y no regrese.